Mixing up a batch of synthetic sea salts is not rocket science.

My mixing vat consists of a 55 gallon white poly drum. In the bottom are a few air stones to aerate and mix. There is also a heater to bring the solution up to tank temperatures. About once a month, I hose out my mixing vat, and find whitish-brown “potato chips” in the bottom. With the tank being white, I also see a significant amount of a brown film on the inside walls. I’ve seen this time and time again, and it is obviously material from the salt mix that is not dissolving.

I decided to look into this and figure out what’s going on. My main concern is that I’m leaving behind important elements/minerals. It turns out that I am.

First, a quick background on synthetic sea salts. They are NOT made with evaporated seawater. If you took some evaporated sea salts and mixed it with freshwater then used it in your marine aquarium, all of your animals would die. This is because when seawater is evaporated, the dissolved minerals and elements that are bound to each other break apart and then recombine with other compounds in such a way as to change the composition entirely. For example, one compound that forms is Calcium Carbonate, which will not dissolve back into solution at the pH of either fresh or saltwater. So sea salts must be made by taking dry chemical compounds and combining them in such a way as to approximate the concentration of all the ions in natural seawater when it is mixed with fresh water.

All salt mixes are based on the original McLachlan (1964) recipe. In the late 1960′s, many more recipes came out that were maximized for the type of organisms to be grown. When you mix up a bag of sea salt,  is the water just like that found in Fiji or Florida? The answer is neither. The waters around Fiji differ from those off the Florida coast by variations in elemental concentrations. The major ions are pretty close, but the minor ions like Cobalt, Beryllium, Zinc, etc., are in different proportions. So mass market salt manufacturers must have a recipe that represents the “average” major and minor elements found throughout the world’s ocean. The actual recipes of salt manufacturers are guarded secrets, just like the recipe for Coca-Cola. You will never find a list of ingredients on either a bag of salt or a can of Coke.

Most salt manufacturers have come up with new “blends” to choose from. Examples are Seachem’s “ReefSalt” and Instant Ocean’s “Reef Crystals”.  The marketing literature sites “chemically sound blend of salts designed to replicate natural reef waters“. Once again, we have no list of ingredients, so what does this mean? With our limited hobby test kits, all we can measure is perhaps higher levels of alkalinity and calcium. If this is your goal, it is easier and less expensive to add supplements to your newly mixed batch of seawater.

It turns out that my brownish-white potato chips in the bottom of my vat consists mostly of calcium carbonate, created from the calcium chloride and carbonates in the salt mix. This means that my freshly made seawater will be low in both calcium and alkalinity, or at least lower than what the manufacturer intended them to be. And the brown film is natural clay that was added to the mix as an anti-caking agent, which is inert and has no effect on the quality of the water.

After researching this and trying different solutions, I came up with a method to not only eliminate the “potato chip effect” but creates consistent and superior seawater each time.

Mix the Whole Bag- Salt manufacturers go to great lengths to ensure that a single bag of salt mix contains all the elements in the right proportions. Many trace elements may constitute just a few grains in the bag. For example, a drum of commercial salt mix that mixes up 1,000 gallons of seawater contains 300 lbs. of Sodium Chloride but only 7 micro-grams of Aluminum Sulfate. To maintain consistent trace minerals, buy bags in proportion to your mixing regime. In other words, if you mix up 50 gallons at a time, buy 50 gallon bags. If you mix 10 gallons at a time, buy 10 gallon bags.

Equalize the PH- Whether you use tap water, RO/DI, or any other prefiltered source water, aerate the water for several hours before adding the salt mix. This is easily done by placing some inexpensive plastic air stones in the bottom of your mixing vat.

Don’t Heat The Water- Many chemical compounds (especially Calcium Carbonate) dissolve faster in cold water. This one step alone will greatly diminish the calcium deposits in your mixing vat. The colder the better. You can heat up the water later when it is fully mixed.

Don’t Create a Slurry- If you dump the whole bag in at once, it quickly sinks to the bottom and creates a slurry where certain compounds (again, calcium) won’t dissolve properly and come out of solution. It is best to add small amounts at a time (one-third of the mix) and let it dissolve for an hour and then repeat.

Don’t Mix High- Don’t try to make a super concentrated seawater mix that is used later by adding more fresh water. No salt mix is designed to be consistent at very high salinity levels.

Adjust to Match Your Tank- Many aquarists complain that after a major water change, their calcium and alkalinity levels get messed up. If you keep your aquariums at certain calcium, alkalinity, magnesium, etc. levels, then adjust your newly mixed seawater to match it.

This is quite easy to do. You only need to figure out the amount of additives to use one time. As long as you mix the same amount of water and use the same brand of salt, just add the same amount of additives each time. This is less expensive than using a premium salt blend, and you probably won’t find one that exactly matches your tank parameters.

By using these methods, I think you will find a better consistency from batch to batch and a more complete seawater mix for your water changes.

Whether you’re a beginner or a seasoned aquarist, choosing lights can be a daunting task. In this two part article, I will attempt to describe what aquarium lighting is all about, and how to choose the best lighting set up for your particular needs.

Light is not always white. The color of light is called color temperature. It is based on a hypothetical model called Blackbody Radiation. I won’t bore you with the theorems, but give you a analogy you can work with. Picture this. You have this big block of black iron, maybe 3 feet across in all directions. You put it in a furnace, close the door, where you can watch it through a little window. There is a temperature dial on the wall, and you start turning it up until the furnace gets real hot. When the temperature of the furnace reaches about 1,500 F, the block of iron is so hot that it starts to glow a dull red color. You then crank it up a bit higher until the temperature gauge reads 4,000 F. Now that block of iron is really toasty. It’s so hot it changed from red to a bright glowing yellow color.

At this point, the yellow color you see is the same color temperature as a 40 watt incandescent light bulb. If we convert 4,000 degrees Fahrenheit to the Kelvin temperature scale we get 2,477 degrees Kelvin or 2,477K for short. A regular old incandescent light bulb has a color temperature of 2477K. It doesn’t matter if its a 40W bulb or a 300W bulb. The 300W bulb will be brighter, but both bulbs have the exact same the color temperature.

Just for fun, we continue to crank up the furnace even higher. When we reach 5,500 degrees Kelvin, the iron starts to glow a bright white color with not much yellow in it. This is the color temperature of the sun (5,550K) as it strikes the earth. If you continue to crank it up even higher, the iron will glow in a crisp white color. Now we’re at 10,000K. A little higher still and the iron begins to change color again. At around 15,000 degrees it is so hot it goes from white to a bright blue color.

Since we were kids, we were all taught that red is hot and blue is cold. In reality, red is hot and blue is much hotter.

This is how color temperature works. It is a measurement of color given off by an imaginary, theoretical object when it is heated to a certain temperature. But its not all theory. In nature, lava flowing out of a volcano has a temperature of around 1200 C, which is 1473K. Amazingly, the color temperature of molten lava is exactly the same as its real temperature.

We can’t always see correct color temperatures. Our eyes can play tricks on us. Humans have the ability to change the color temperature of what we see on the fly. And it’s completely autonomic so we don’t even know it’s happening. Our eyes and brain create our own “white balance”. In other words, if the lighting is different than the sun, we will see the light as white once we are exposed to it for a short period of time. A good example of this is the standard “cool white” fluorescent bulbs. They have a color temperature of around 3400K, which is a very yellowish, almost greenish light. But once you’re in an office building chock full of cool white fluorescents, it only takes about 10 seconds for your eyes to adjust to it and see it as a white light. If you take a picture under cool white bulbs using a conventional film camera (with no flash) the photograph will have a definite yellow cast to it.

Our eyes are most sensitive to light in the 3000K-4000K range. In this range we “see” light much brighter than it really is. This is why cool white bulbs were invented in the first place-to get the most bang for the buck. Or better put, to get the brightest light for the watts. While cool white bulbs and conventional fluorescent fixtures are cheap, abundant, and give humans bright light, they are not suitable for use in most marine aquariums.

The color temperature of the sun is often sited to be 5500K. So why don’t we all use 5500K bulbs on our marine aquariums? First off, when the sun’s rays pass through our atmosphere, certain bands or wavelengths get filtered and change the color temperature. The sun’s color temperature can appear to us in a range of 2,000K (sunrise/sunset) to 30,000K (cloudy skies over the ocean). So 5500K is used as the standard for “midday sun over the equator”. The color temperature of pure sunlight at the surface of the ocean is 5500K. BUT-as the sun light penetrates through water it is unevenly filtered and refracted, which changes its overall color temperature. The infrared color band is completely gone within the first 1 meter of water depth, as is most of the lower wavelengths (predominantly reds and yellows). Within 3 meters, the color temperature changes to almost double the sun’s original value, or roughly in the range of 8000K -10000K at a depth of 3 meters.

If you’re keeping corals or inverts that live in atolls or shallow tide pools, then 5500K or 6500K bulbs is really the optimum choice. Fish look good under these bulbs. Your tank looks very bright, though most people see this as a yellow-tinged light.

Aquarium bulbs are now available in a wide variety of color temperatures. In the last few years, 20,000K bulbs have become very popular. They simulate color temperatures at ocean depths beyond 15 meters. Most all of the tropical corals and inverts sold into the trade don’t live at these depths. But people like the blue color of these lights, despite the fact that they are not optimal for coral growth. Most commercial coral farming operations use 5500K and 6500K bulbs.

What about Actinics? Do they have a color temperature? Yes, it’s 7100K but the number is somewhat meaningless. This is because color temperature is the average of all the wavelengths (or colors) that come out of the bulb. For all practical purposes, Actinic bulbs only give off one narrow spectrum that lies between the bands of longwave UV and the lower visible blue spectrum. You’ve seen or read the ads that claim “True Actinic – 430 nm”. The “nm” stands for nanometers – it is another measure of light which defines its full-wave frequency, called the wavelength. In general, we don’t really care about this.

So why do we use Actinics in the first place? Actinic bulbs (or the correct name for this spectrum of bulb, “Actinic 03”) was not developed for the aquarium industry. They were invented for the health care industry to treat jaundice in infants. Jaundice is a disease that causes the skin and whites of the eyes to turn yellow, usually because of poor liver function. When exposed to the Actinic 03 bulb, the light would increase vitamin synthesis on the skin, which battles the disease. As the story goes, somebody at the hospital took one of these bulbs home because he thought it would look cool over his marine aquarium. Not only did it look cool, but it had a marked increase in livestock growth. Whether this story is true or just another reef urban legend, the fact of the matter is that the Actinic 03 bulb has a wavelength that is pretty much dead center on the peak value required for marine photosynthesis.

Many of us use fluorescent lighting fixtures containing one or more 10K bulbs with an equal number of Actinic bulbs. Flip the fixture over and look at the bulbs. Those 10K bulbs look ten times brighter than the Actinics. However, they are brighter only to our eyes. Those of us who use light timers or controllers to sequence the lights on and off usually turn on the Actinics first, followed by the 10K bulbs. In the eyes (or photo-receptors) of your corals, this is backwards. The Actinics are far brighter to them than the 10K bulbs.

Actinics are very important because they supply a relatively large amount of light in the right wavelength. Think of it this way. If you wanted to reproduce the wavelength and brightness of an Actinic bulb using a regular bulb over your tank, you would probably need several thousand watts to get there.

In the next installment, we’ll take a  look at all the different  bulb types, and determine if one type is really better than another.

There have been many algaecides available over the years for freshwater aquariums, but this is the first time in recent memory that a marine-specific aquarium algaecide has become available and so heavily promoted.

The product is called AlgaeFix®  Marine, manufactured by Aquarium Pharmaceuticals, Inc. The label claims it will control green algae, slime algae, brown algae, and filamentous (hair) algae. It is marketed as a reef-safe product harmless to fish, corals, and invertebrates, without the usual soft invertebrate exceptions found in the fine print.

I decided to put this product to the test. I had a great candidate for testing, a 100 gallon FOWLR tank with some awesome growth of Debersia, Bryopsis, and other unknown strains of green hair algae. This tank also has a copious amount of red cyanobacteria covering the rock work and substrate. The livestock includes the usual cleanup crew (snails, hermits, urchins) a few rocks with various zoanthids, and a variety of marine fish including a Blue Tang (Paracanthurus hepatus), Deepwater Anthais (Pseudanthias pleurotaenia), Marine Comet (Calloplesiops altivelis), Singapore Angel (Chaetodontoplus mesoleucus), Pajama Cardinals (Sphaeramia nematoptera) and Perc Clowns (Amphiprion percula).

Before I dumped in my first dose, I wanted to know what’s in this stuff. To my surprise, I discovered the active ingredient was not a broad spectrum herbicide but a biocide called dimethyliminoethylene dichloride. After a little digging, I found that it is manufactured by Buckman Laboratories of Canada under the brand  name Busan® 77. This is an industrial liquid biocide use to kill algae in everything from commercial swimming pools, hot tubs, decorative fountains, swamp coolers, and air wash systems.  Busan® 77 is sold at a concentration of 60%, while AlgaeFix® is at 4.5%. So it appears to be a watered down version of the same compound. It is not approved for use in potable water. To be fair though, this just means that the manufacturer hasn’t gone through the testing to satisfy EPA regulations.

Now all this sounds very nasty, but many compounds act differently at different doses. For example, arsenic is present in natural seawater and believed to be beneficial at its natural concentration. All compounds, synthetic or otherwise break down over time and become inert. Some do this in a matter of minutes, while others may take months or years. API claims that Algaefix® does so in 24 hours.

There are two versions of Algaefix® on the shelves. One for freshwater and one marine. Both products are identical sans the labeling. So if your retailer charges more for one or the other, choose the lowest price version.

I prepared the test aquarium so the product had a fighting chance without external influences. I physically removed as much algae as I could, performed large water changes, added a phosphate remover, and got both phosphates and nitrates to undetectable levels on two different brands of hobby-grade test kits (Elos and Seachem).  I gave it a week to settle down before the first dose. The directions make no mention of turning off protein skimmers/UV/ozone or removing activated carbon, so I left the protein skimmer running, the UV bulb burning, and the carbon in the sump.

The label dosage is 1mL per 10 US gallons, dosed every third day.  It doesn’t say how long to do this,  just “until algae is controlled”. After the first week, I saw no changes. In fact, the hair algae continued to grow. The second week was the same. After 7 doses (3 weeks) there was still no effect on either the hair algae or the cyano.

I decided to up the ante and dose 1.5mL per 10 US gallons every other day, effectively doubling the dosage.  After a week of this, the only visible change was that the hair algae was either not growing anymore or growing at a slower pace.

During the middle of the next week, I began to see small tufts of hair algae floating around the tank, heading off and gathering on the overflow grille. I reached into the tank and pulled on some hair algae. To my surprise, it came off very easily.  Everyone knows how tough hair algae attaches to objects, well I could almost peel it off the live rock in mats. Interestingly, the algae was still green as ever but had no holding power. I really expected to see a bleaching event similar to “macroalgae going asexual”, but this never happened. While the algae was weak, I found this to be the perfect opportunity to perform a water change and siphon off all that I could. I probably removed over half of the hair algae in the tank just by rubbing the end of the siphon hose lightly over the live rock.

On the negative side, the few cyano patches that were present before dosing had grown. In fact, the red cyano was taking over. I don’t necessarily blame Algaefix® for this. In all likelihood, a huge increase in DOCs was probably occurring and the skimmer + carbon couldn’t keep up. Although I did see some increased skimmer production, it wasn’t the “cup runneth over” scenario you get when dosing AZNO3. Nevertheless, the product does claim to control slime algae and I saw just opposite.

I stopped dosing at the end of the week and performed another water change. This time I was able to remove nearly all the hair algae in the tank. I left a few tufts behind as food for the urchin. I saw no ill effects in either the fish or inverts in the tank. I was particularly concerned with the urchin’s health as this creature was actively eating the hair algae during the peak of my double dose treatment. It’s been several weeks now and the urchin still looks healthy and active as ever. The red cyanobacteria bloom subsided on its own, with a little help via a thorough skimmer cleaning and regular water changes. I did experience an alkalinity drop ( from 2.8 meq/l to 2.0 meq/l) during the treatment and a subsequent ph drop from a daily average of 7.92 to 7.84.  A little carbonate buffer added during the treatment brought these levels back up.

In conclusion, I find that this product to be very effective on hair algae, providing the aquarist perform physical removal during the treatment period. It does nothing for red cyanobacteria, and may actually make it worse during treatment. Keep in mind that the test aquarium did not contain any SPS or LPS corals, so I can’t comment on the effects of the product in this regard. I also experienced a higher than normal carbonate depletion, so I advise to monitor and correct alkalinity accordingly during treatment.

The labeling states a maintenance dose of 1.0mL per 10 US gallons weekly, once algae is under control. I did not have time to test this. Perhaps this will become the topic of a follow up entry in my blog.

At one time or another, all of us have chased fish around an aquarium until either you or the fish gets exhausted and gives up.  This frustrating practice of chasing fish with a net, causing extreme cloudy water, and eventually moving/removing every piece of decor or live rock is not the best way to catch fish.  The fish not only get stressed (not good if the reason for removal is disease treatment) but suffer considerable damage to the protective mucus layer as the fish scrapes itself on rock and your fast moving net.

I’ve been doing this years. With all of us using more live rock in both reef and FOWLR tanks, it is becoming near impossible to remove fishes the old fashioned way.

Recently, I wanted to remove all the fishes from my 60 gallon reef tank. I wanted to do this not because of disease treatment, but to experiment with a persistent nutrient/algae problem to see how much the fish contributed to the nutrient load.  Like most reef setups, I have live rock stacked almost to the top of the tank along the back wall.  One of the fish in there is a small 1-inch Goby that darts in and out of tiny crevices in the rock. Even if I removed every piece of rock, trying to find which piece the Goby would be hiding in would be a nightmare.  Besides, many of my early SPS frags have grown out across the rock “fusing” them together, and there no way to get the rock out without breaking corals.

Frustrated by this, I went looking for fish catching alternatives.  Anthony Calfo has spearheaded this effort with several threads and articles. I decided to try some of these methods and see how well they actually work.  So here is a list of fish catching methods supplemented with my own experiences.

The Drain Method

When I first read about this, It sounded like too much work for me. Basically, this method involves draining the tank. Yikes! If I’m going to do that, I might as well remove all the rock and use a net!

Believe me, this is so simple and quick you have got to try it. I caught all the fish in my reef tank (including the tiny Goby) and had everything back the way it was in less than 30 minutes. Not one piece of live rock was moved.

Go to the hardware store and get one or two Rubbermaid trash cans, depending upon the size of your tank. Also pick up a 8-foot length of one-inch diameter vinyl tubing. You set the trash can in front of your tank and use the tubing to siphon out the water.  On my 60 gallon tank, it took less than 3 minutes.  You can move a lot of water through a 1-inch hose very quickly.

As I was draining it, I saw none of the fish as they were all hidden in the rock structure.  My first thought was that they’ll be trapped in the dry rock crevices as the water level dropped. Amazingly, as the water got down to maybe 3-4 inches, all the fish instinctively swam out of the live rock and congregated right in front of the tank. I just took my net and scooped them out.  The smaller fish swam across the front of the tank, but all in all there was very little chasing with my net. Next time I do this I will dig out a section of gravel and make a little depression where I believe the fish will all congregate.

To refill the tank, I dropped a submersible pump in the trash can and let the return hose run water over the live rock (like a waterfall) to prevent stirring up the sediment. The refill process actually took the most amount of time, probably 10 minutes to get the tank filled up again. If I had a bigger pump on hand, I probably could have filled the tank almost as fast as I drained it.

I can assure you that the short period of time that the live rock and corals were out of water causes no harm. Live rock is shipped dry and remains so for days during shipping. Corals quickly “slime over” with a protective layer when removed from the water.

If you’re tank is less than 100 gallons, please try this method because it really, really works with minimum effort.

The Corral Method

For tanks over 100 gallons, the drain method is not too practical since you need a lot of trash cans. My second choice (which I have used many times with 100% success) is the Corral Method. Like rounding up cattle from a pasture, you create smaller fenced in areas in your tank where the fish have nowhere to go except into your net.

Get some eggcrate from the hardware store. You need to make two identical panels. The width of the panels is the inside width of your tank (front to back). The height of the panels are the water depth in the aquarium  plus 1 inch. The idea is to place these two panels into the tank on both sides of the fish, trapping it in a small area. You stick the panels down into the gravel, and the top of the panels stick out of the water. Wrap the end with duct tape so the edges of the eggcrate won’t scratch your tank or hands.

When you start messing with your tank, the fish will bolt into their favorite hiding places. Most likely, this will be behind or in a piece of live rock. If your aquarium is aquascaped with several “islands” of live rock across the tank, it’s easy to place the partitions on both sides of the island where the fish is hiding. Once cordoned off, you may need to remove a piece or two of live rock in the corral zone to get at the fish.  It will usually swim out in a frenzy and be stopped by the eggcrate panels on the left or right, where you can easily net the fish without much chasing

If your live rock is situated as a continuous row across the tank, you will have to move some pieces around to make some narrow slots down the gravel for the partitions to fit in. It is best to let the fish hide on its own, observing where the fish likes to go when threatened. Clear a narrow area on both sides of the hiding place.  As long as you don’t move the rock where the fish is in, it will stay put as you get the partitions in place. If the fish is small enough where it could pass through the holes in the eggcrate, wrap it fiberglass window screening before applying the duct tape.

There is a little bit of work in making the eggrate partitions, but once you have them they can be used over and over.

The Bait-and-Switch Method

In an established tank, your fish probably race over to a certain spot where you feed them every day, hovering right at the water surface to get some tasty food. Perhaps some even taking it directly from your fingers. This method involves food in one hand, and a net in the other.  At the right moment, you simply swipe the net quickly down into the water, capturing the fish while its mind (and mouth) are on the food.

This has worked for me, but not every time. Fish can bolt away very quickly when they see the net.  If you miss, you won’t have the opportunity to try this again for several days or even a week.  Fish learn about the net trick very quickly and will become skittish at feeding time. This method works best if you’re trying to a catch a single fish. It is not practical to catch every fish in the tank or any fish that doesn’t eagerly come to surface to feed.

The Night Stalker Method

This method involves catching a fish while it is sleeping. It only works for fish that sleep out in the open like Clowns, Cardinals, etc. Some fish will “drift” to the open while it sleeps, so you may have to time this a bit.

You need to make sure the room is in total darkness. If you have moon lights, cover a few of them with pieces of black electrical tape. Without moon lights, you can use a small flashlight such as a Mag-Lite. Some people say to cover the lens with a piece of red cellophane tape. I’ve tried it both ways and it doesn’t make much difference.  Just don’t point the flashlight right at the fish- point at the back of the tank or off to the side.

Wait a few hours after the tank lights go out, then take a plastic specimen tank (a.k.a “convalescent home”) and VERY SLOWLY submerge it.  Move it under the fish and raise it out of the water. voila!  You’ve caught your fish. Be sure and move it to your holding tank without turning on any lights.  If it wakes up, it will likely panic and jump out of the specimen tank.

The “Gone Fishing” Method

This method involves using a fishing hook and bait. This is no joke. Catching a fish in this manner is a lot less stressful than chasing it around the tank for 30 minutes. The lip injury caused by the hook heals quickly and causes no harm. Think about this. There are thousands of anglers who exercise the “catch and release” method in sport fishing to maintain fish populations- and it works.

Go to a sporting goods store and get some small trout hooks. The smaller ones (size #18 and higher) are small enough to accept a single mysis shrimp. Use a small file to remove the barbs, which will minimize lip damage and make it easier to remove the hook. Drop your line in and wait. When you hook the fish. use a plastic specimen tank to remove it from the water.

The Bag in a Bag Method

This is a method created by Anthony Calfo. It is a way to catch really shy or elusive fishes in a reef tank. Dwarf Angels, Basslets and the like can be had this way with little disturbance to the tank as long as you have a little bit of patience.

Take a fairly large plastic bag (new and sturdy 2-3 mils preferably). Size is relative to the fish being caught. But typically a 10X22 bag catches most home reef aquarium fishes. Fold the top of the bag down about 2 inches to make a sturdy collar and sink this bag into the aquarium while removing all air from in and under it (the collar). Place the bag expanded (fluff it out so it is a bit spacious) in the aquarium. MOST IMPORTANTLY lean it against the rockscape so that shy fishes are more likely to slip by or in it.

The Bait: cut the corner off a plastic sandwich bag and put some frozen brine shrimp in it then tie it off, then throw it into the back of the large sunken bag trap. Then with a bowl of additional live brine shrimp in a slurry, you sit near the tank (lights off in the room) and occasionally squirt with a turkey baster just a little bit of brine shrimp into the mouth of the bag every few minutes as needed. The obvious ploy here is to lure fishes to the mouth of the bag and tease them with the “motherload” in the back! (the small tied off bag of concentrated live food).  Now of course every other fish and its brother that you do not want to catch will enter the bag first. But eventually the shy fish will too… and when it does, you are sitting several feet away from the tank with a piece of fishing string that was tied around the neck of the bag, under the collar… and pull! You’d be amazed how well this works for really elusive fishes. It takes time though… and patience. But if you are afraid to drain your tank or use other methods, this may be an option.

In summary, these are the most popular methods for catching fish, but there are also lots of other ways that people do it. Some of these include the 2-liter soda bottle trick where you cut off the top and invert it, placing it back in the bottle to form a funnel. Some people have had success with placing a small mirror in the tank. The fish gets so obsessed in chasing its own reflection that you can scoop it up easily.

whatever method you use, don’t get frustrated and wind up tearing your tank down to catch a fish. Use one of these methods and you will relieve the stress for both you and your fish.

These people post reports of success prematurely, and you never hear about the tank crash or the severe algae outbreak that happened a month later. Unlike keeping cats, dogs, and reptiles, successful reefkeeping is still in its infancy and we are all learning, from the marine biologist to the home nano-reef keeper.

A successful reef aquarium can be defined as just two objectives: good coral coloration and good coral growth. If you get there on your own, you can be proud that you made it- despite everyone telling you to try this or that, or weeding through tons of misinformation on the web. Keeping corals healthy and thriving is hard work, but the rewards of seeing your “slice of the reef” grow and thrive is all worth it. The trick is coming up with your own recipe for success.

Equipment and additives always take center stage in aquarium care. But feeding corals is often misunderstood or neglected. At the LFS, I cringe when I overhear beginners pointing to specimens and talking about photosynthetic versus non-photosynthetic corals. The usual advice is, “If you buy that one, you’ll have to feed it”.

Well folks, all living organisms on the planet have to feed. While it is true that photosynthetic corals have evolved to withstand bouts of famine, all living creatures need to eat sooner or later.

Non-photosynthetic corals naturally grow in caves and narrow passages, where current flows constantly bringing in a constant supply of food particles. They are used to eating all the time. Interestingly, almost all non-photosynthetic corals are very hardy and quite tolerant of poor water quality, unlike their photosynthetic cousins. Think of these corals like marine fish (which by the way, are also non-photosynthetic). They have to be fed regularly, at least once a day. It all boils down to feeding the right foods on a regular basis. But whether your talking about photosynthetic or non-photosynthetic corals, food is the key to success.

I tend to think that my SPS corals are like my vegetable garden. I was careful to pick a spot that gets lots of sun, and spent some time picking out the right fertilizer to match the types of vegetables I’m growing. With both sunlight and fertilizer I will get a nice crop of tomatoes, green beans, and bell peppers all summer long. I once skipped the fertilizer and wasn’t very happy with the results. The look and size of my vegetables were unappealing.

I use the same philosophy with my corals. Without proper lighting and without proper food (fertilizer) my corals won’t have the bright coloration and rapid growth that they should. Oh, they’ll survive, but they just won’t thrive.

There is nothing more frustrating than spending $50 to $100 for an SPS coral with beautiful colors, only to have the colors fade or turn brown after a month in your aquarium. Sometimes just the tip color is gone, the polyps barely open, or small bleach spots appear at the base. While additives such as calcium, magnesium, and strontium play an important role, nutrition is the number one factor affecting coloration and color loss.

Biologists have always viewed corals as unique in the animal kingdom. They are the only organism that has dedicated over 70% of its body to feeding appendages.

They are literally covered with mouths. In 1931, C.M. Younge stated, “When an animal possesses an organ or set of organs which perform certain functions with perfect efficiency, it can be taken as axiomatic that such organs are used.” Bottom line: these guys are designed to eat.

Photosynthetic corals do not use light themselves as any form of nutrition. Instead, there is a micro algae living inside the skeleton called Zooxanthellae (pronounced zoo·ant·the·lay). This micro algae is symbiotic with the coral, just like the clownfish and the anemone. Like all algae, it lives by photosynthesis and converts light to carbohydrates (sugar). These sugars, being in close proximity to the coral tissue provide the animal with a source of carbohydrates (but no proteins). In turn, the coral’s waste provides nutrients for the algae.

70% of coral surface area are covered with “mouths”

It’s important to understand that this algae is not attached or biologically connected in any way to the coral’s tissues. It just sits near the tissue as a separate, living organism. When food sources containing protein are ingested through the polyps, the sugars act as a catalyst to create a complete source of nutrition for the coral.

So in order for the symbiosis to work, the coral has to ingest proteins so it can feed the algae. In other words, Zooxanthellae requires that the coral eat solid food in order to survive. This is the symbiosis. Since corals derive there color from the Zooxanthellae, this is why lack of food causes the colors to fade.

You and I (and your corals) may be able to survive on sugar alone, but we just won’t get everything we need in terms of nutrition to remain healthy and in top condition.

Corals do derive some food from detritus, amino acids, and other compounds in the water column. At one time it was believed that ‘turkey-basting” Live Rock and getting detritus suspended in the water would provide sufficient food for corals. It has been found that the protein level of detritus is so low that the energy required to feed far outweighs any benefits. Ironically, the best looking reef tanks with crystal clear water are the worst environment for the natural feeding of corals.

Microscopic View Of Zooxanthellae

Fortunately, SPS corals are very easy to feed. I use a combination of foods and vary the recipe a bit from time to time. Like marine fish, we don’t know what constitutes the Acropora diet, so using different combinations of food sources is your best bet.

There are powdered coral foods available such as Coral Grow, Coral Frenzy, and Reef Roids that form the base of my coral mixture. I also add some frozen foods, such as oyster eggs, prawn eggs, or frozen Cylcop-eeze. Particle sizes greater than 100 microns are too big for feeding most SPS coral polyps. Save your Mysis and Brine shrimp for your LPS’s.

If you prefer, you can buy ready-made frozen foods suitable for filter feeders. There are many products available from your LFS that will do the job. I have found that these commercially prepared products are highly concentrated, so use only small amounts until you get a feel for how much to feed. Frozen fish foods, with or without gelatin binders are unsuitable for corals because particle size varies considerably.

Basic coral feeding ingredients

I mix up my coral food a few minutes before I feed. I don’t create frozen blocks of coral food ahead of time, though many people do. I first put a few ounces of tank water in a small cup (don’t use freshwater) and add about 1/8 teaspoon of powdered coral food. I will then add a small amount of frozen food which most of time is a frozen chunk of Cylop-eeze. To enrich the mixture, you can add a few drops of Selcon or a pinch of dried Spirulina (available as a powder at most health food stores). I stir the mixture for a few seconds and then I’m ready to feed.

You want to do what’s called “target feeding” your corals. Just dumping the mixture into the tank is a waste, as only a minute amount of the food will actually be consumed by the corals. Target feeding is easy to do and can be done with an eye dropper or my preferred method, using the Kent Marine Sea Squirt. This is basically a giant eye dropper with a built-in extension that no reef aquarist should be without. Turn off all circulation pumps, return pumps, etc. to make the water still. Suck up some of the mixture into the Sea Squirt. Place the tip of the eye dropper about an inch away from the coral and squeeze the rubber bulb. The coral will be covered by a cloud of the mixture. You will see the polyps close around the food particles. Move to the next coral and do the same thing. Be careful not to touch or hit the coral with the tip of the eye dropper. Doing so may cause the polyps to retract and the coral won’t eat.

“cloud of food” during coral polyp feeding

This all sounds complicated but it’s really easy to do. You don’t have to be precise in spraying the food, as it will disperse around the coral. From the time I mix the food and feed the corals, the whole process takes me less than 5 minutes.

After feeding you will see some stringy slime rising out of some corals. This is normal and nothing to worry about.

I usually turn the circulation pumps back on right way, but keep the skimmer and return pump off in order to keep the food particles circulating around the tank. I then turn everything back on in about 30 minutes. An added benefit: any uneaten food particles will work there way to the live rock and boost your pod population.

My normal feeding regime is twice a week. I have never had a nutrient problem due to feeding. If you’re worried about this, plan your water changes so you do them the day after you feed. A 50 – 75 gallon tank packed full of SPS corals won’t need more than 2 ounces of liquid food at any given time. I would suggest that you start sparingly and feed frequently. There is no hard fast rule on how often you should feed corals. Twice a week is adequate for most setups. If you’re trying to accelerate the growth of frags, then feed once a day.

Many of the things we do to improve our reef aquariums takes weeks or even months to see results. Not feeding. The effects can be seen in less than 24 hours. Observe your polyp extension just before you feed. The next morning after the lights have been on for a few hours, look at your corals again. you will see a pronounced polyp extension as the corals seem to be saying “give us some more!”.

Every aquarium at one time or another experiences a bloom of brown algae. You are most likely to see it during the cycling phase of a new tank or while curing Live Rock. Brown algae can also show up at any time in well established tanks.

Brown algae is not an algae at all, but a tiny animal called a diatom. The animal is encased in a hard shell made out of silicone dioxide. The brown mats and film you see are composed of billions of diatoms interlocked together by their hard shells. They come in a variety of shapes and sizes and is the most common phytoplankton on the planet.

The appearance of brown algae in an aquarium is most often blamed on silicates in the tank water. Just like SPS corals that require calcium to grow, diatoms require silicates to grow. However, there are many other factors that cause brown algae and I believe the excess silicates story is way overplayed.

The use of “play sand” or silica gravel in a marine aquarium is often cited as a cause of diatoms. The silicates in these substances are bound up chemically much the same way as it is in glass. In fact, the glass panes that make up your aquarium is pretty much 100% silicates. The notion that play sand is a cause of diatoms is nothing more than another “reef legend”.

Almost every newly set up tank, during its cycling period, experiences a brown algae bloom. Even tanks with nothing but water and a layer of aragonite gravel will get it. Then if by magic, the brown algae begins to recede all by itself and is replaced by green algae.

During cycling, there is a time when the water contains high levels of dissolved organic carbons (DOCs) and nitrites, but low levels of nitrates and phosphates. It is these condition where diatoms seem to thrive. Minimizing their growth can be accomplished by turning the lights off during cycling. These are photosynthetic creatures and will not do well in subdued lighting. Secondly, performing large water changes and/or aggressive skimming during cycling will reduce their growth.

In established tanks, brown algae blooms are often times accompanied by some Cyanobacteria (red slime) as well. This is clearly an indication that it is an organics issue. Generous use of carbon and wet skimming will solve this problem.

When a brown algae bloom does occur, it is important to remove as much of it as possible. Similar to red slime, brown algae tends to “feed itself” through a die off and growth cycle that becomes self-sustaining.

Too much iodine in the water leads to brown algae. Even if you don’t use Lugol’s solution, check the label on any additives you use. Many contain significant amounts of iodine.

On rare occasions, excess silicates can be the cause. If you suspect this, phosphate removers also remove silicates. If you run phosphate removers all the time, it is highly unlikely that silicates are to blame. Still, silicates can get into your tank in a variety of ways. Using tap water or well water for topoff or salt mixing is a major source. Frozen Foods are another, though probably not a significant source.

Very high nitrate levels, even when phosphate and organics levels low will cause brown algae. No one knows the mechanism of this. Safe to say that It is prudent to keep nitrate levels low not only to prevent brown algae, but to prevent health problems with specimens in the tank.

Tanks with a good growth of green algae never seem to have brown algae problems. Perhaps the greens compete for nutrients, or more likely green algae consumes unknown compounds required for diatom growth. Whatever the cause, if one was to choose the lesser of two evils, green algae would be my choice.

The Berlin Method is simple. It includes only three items to do all aquarium filtration: Live Rock, an overflow with mechanical filter, and a large Protein Skimmer.

Each of these items work together to complete the filtration picture. The Live Rock performs the function of a biological filter and provides nitrate reduction. The mechanical filter removes detritus and algae that naturally accumulates due to the metabolism of the invertebrates. And the protein skimmer removes nitrates, phosphates, and DOCs (dissolved organic carbons).

It’s been over thirty years since the original publication, and no one has come up with a better way to filter a reef tank. Sure, we now have Sulfur Filters, Phosphate Reactors, and a slew of other equipment at our disposal. But all this extra junk just boosts the power of the original Berlin design.

Somewhere along the way, many hobbyists decided that the mechanical filter in the Berlin Method was not necessary. Some go as far as stating it’s downright detrimental in keeping corals. The reason you most often hear is that mechanical filters remove pods and zooplankton that otherwise would feed the corals in the tank.

Quite frankly, this is bullshit. And here’s why.

No one can grow or sustain zooplankton in a reef aquarium. Period. Zooplankton is an “organism soup” of micro life that lives in the water column, most of which remain in a planktonic state and “free float” for their entire lives. Reef aquariums cannot produce the immense quantities of phytoplankton and other micron-size live food particles to sustain any populations of zooplankton. On the real reef, zooplankton is abundant and is consumed every night by corals and fish larvae. Unfortunately, these microorganisms simply don’t exist and never will in your aquarium. So a mechanical filter cannot remove zooplankton, because there isn’t any to remove.

Secondly, there are the Pods. Copepods, Amphipods, and Isopods can easily reproduce in large numbers in a reef aquarium. But the pods that grow well in our tanks are all benthic, meaning that they are bottom-dwelling creatures that don’t live in the water column. Have you ever experienced your front glass being covered by little white moving dots? These are Isopods. But you may have also noticed that the water didn’t look like it was snowing with them- only surfaces like the front glass and the Live Rock were populated. The don’t swim- they walk. The only way these little guys will feed your corals is if they accidentally crawl into a polyp. A mechanical filter will not remove Isopods unless they lose their footing and get swept into your overflow.

The larger Amphipods are quite common and can be seen crawling around on the Live Rock. As far as pods go, these guys are pretty big at around 5000 microns (about an 1/8-inch) as adults. The have a hard shell with a series of legs underneath and resemble a very tiny shrimp. They are an excellent food for Mandarins and other bottom feeding fish. They are however, too large to feed SPS polyps and too small to feed LPS corals. They guys would have to walk into the mouths of LPS corals to get eaten, which is not going to happen. These pods live everywhere- both in the sump/refugium and in the main tank. Unfortunately, most are too big to survive the trip through the return pump back to the main tank. Again, a mechanical filter might trap a few that get swept away by the current, but not enough to make a difference.

I decided to examine the contents of a used mechanical filter under a microscope. The filter sock I examined was in service for 3 weeks on a 60 gallon SPS reef tank. It’s pore size is 100 microns and composed of spun polypropylene. All of water flowing from the main tank through the overflow passed 100% through this filter. Within the 3 week time period, it was so clogged up that water would not freely pass through it anymore.

I took several scrapings of the material on the inside of the bag and placed it on well slides. The first thing I saw were diatoms (aka brown algae). Zillions and zillions of them. In the photo above, you can see the brown color of the spent filter sock caused by all the diatoms. Surprisingly, there is very little brown algae spots or brown haze anywhere on the glass panels in the aquarium.

Probably 90% of the material on the filter sock was brown algae. But there were also green microalgae and small strands of what appeared to be hair algae in great abundance. As for life forms, there were some very tiny (2-4 micron) single celled organisms swimming around. I don’t believe the 100 micron filter sock had captured these guys. They were just swimming in the droplets of water on both side of the filter material.

Finally, lots of detritus chunks. Many were entangled in a stringy algae mess, some pieces were clearly encased in a bacterial slime. Others looked like small rocks. At least this time, I did not find even one pod in the half-dozen or so scrapings I examined.

So what does this all mean?

While the Berlin Method touts the mechanical filter as a detritus removal mechanism, my own experimentation indicates that it’s main function is that of an algae filter. Both substances are equally harmful to the health of saltwater aquariums. Detritus robs the tank of oxygen and lowers PH and ORP. Algae smothers out invertebrates and causes severe water problems. While many things contribute to algae outbreaks, my opinion is that using a mechanical filter will diminish the occurrence of film algae, and prevent the spread of undesirable macro and hair algae. Besides, once you start using a mechanical filter, you will have the cleanest sump in town.

If you don’t already employ a mechanical filter in your reef tank, give it a try. I believe it is an important component of both algae and water quality control.

I don’t know how many times I’ve seen those fish compatibility charts. I’m sure you’ve seen plenty of them, too. They consist of rows and columns illustrating what species of marine fish can be safely kept together. Some of them go a step further and rate the compatibility as “Safe”, “Generally Safe”, ”Some Caution”, and so on. In my opinion, these charts are practically worthless.

Here’s why. You would never want to keep a Clown Trigger (Balistoides conspicillum) with a Pajama Cardinal (Sphaeramia nematoptera). But you could keep one or more Cardinals with a Niger Trigger (Odonus niger). Likewise, a Sailfin Tang (Zebrasoma veliferum) would get along with any Butterflyfish, but only if the tang is smaller in size. If you’re adding a fish to your tank that hasn’t had a new fish added in 8 months or more, I don’t care what kind of fish you have in there, the existing fish will be aggressive to the new addition- and some fish will remain that way, including the “peaceful” fish from the chart. For these reasons you cannot solely rely on fish compatibility charts in creating your community aquarium.

So where can you go to get all this information? I would recommend that the Internet be your last resort. There is just too much mis-information there. Start with your LFS, who has to deal with separating incoming shipments every week

and knows a lot about fish compatibility. Seek out veteran aquarists who have kept the species you’re interested in and can give you some first hand knowledge. Do invest in a few good books (such as Marine Fishes by Scott Michaels) to learn about compatibility issues and interaction.

When you have gotten to the point where you have selected a list of fish and have researched compatibility to the point where you believe they should all get along, consider the following:

► On a new tank setup, add the most peaceful and/or the smallest fish first. Work your way up from there. The largest and most aggressive fish should be added last. Unless you have multiple quarantine tanks, you will be adding a new fish (or groups of the same fish) at one month intervals. This is a good schedule to be on. It give the fish time to settle in and allows the tank to stabilize and adjust to the new bioload. Any problems along the way (like algae blooms) can be dealt with quickly. While the fish is in quarantine, it will learn to eat the food that you plan on feeding the community tank.

► The method of adding a new fish to an established aquarium depends on the situation. If the new fish is larger than all the rest, you can usually get away with adding the new fish and have some short term aggression. If the fish is small or you have gone a long time without adding any fish to the community tank, place the fish in a plastic specimen box drilled with holes and secure it to the rim of the aquarium. This give the established residents time to recognize the fish and ease away from their strong territorial instincts. Keep the fish in the specimen box for at least 3 days. Some authors advocate an alternative of rearranging the décor and live rock and add the fish directly. This method has not worked for me. It seems that some fish know that they are in the same tank and quickly reestablish territories. Others get so stressed out that their health suffers.

► Some fish do best in groups. For example, Damselfishes and Chromis. You should always keep these fish together through quarantine and when adding them to the display tank. Doing so will not only minimize stress but reduce aggression of existing fish when added as a group.

► During the first 24 hours, the new addition may hide most of the time and skip the first feeding. If it skips the second feeding, it may never acclimate to your tank.

► If the new addition is always in hiding and you never see it, it may have perished from either stress or aggression or both. This may sound crazy, but if the established fishes “gang up” and kill the new addition, you will never be able to add another fish to the tank again.

► If the new fish is harassed to the point where it is cowering in a corner, remove the fish immediately (or its aggressor). I have seen this happen on several occasions and can say that this level of stress will kill the fish in 24-48 hours, even if there is no fin damage.

► “Chasing” for the first 24 hours is normal for a new addition, but fin nipping is not. If there is significant fin damage even though the fish is swimming around and not huddled in a corner, you need to remove the fish as soon as possible. Place it back into quarantine until its fins are healed, and use the specimen box method to re-introduce it.

► For larger tanks, you probably feed your fish in the same area every day, perhaps on the left, right, or middle of the tank. Don’t confuse your fish by adding a new addition in the same location where you feed.

► If you cycle your lights down at night (perhaps turning off daylight bulbs before actinics), add the new fish when the lights are at their lowest level. But don’t add a new fish in total darkness. Some people advocate adding the fish during feeding or immediately thereafter. Personally, I’ve tried this and it doesn’t seem to make any difference. After all, territorial aggression is based on establishing a breeding nest and has nothing to do with food.

► Don’t add a new fish and go off to work. You want to stick around and check on it from time to time to make sure the acclimation is going well. Watch from a distance. Rapid movement right in front of the tank just adds to every fishes stress level.

► Once the new fish is settled in you might see some occasional chasing, which is harmless. This will subside over time.

In the aquarium trade, activated carbon is sold in more products than you think. It is the key ingredient in HOB disposable filter cartridges, and is often blended with ion exchange resins, ammonia removers, and other chemical media that makes up hundreds of aquarium products . And of course, it is sold in bulk or pure form for use in canister filters, mesh bags, and media reactors.

Why do we keep using it? Any veteran freshwater or marine aquarist can tell you that it removes odors, removes color, and makes aquarium water as clear as ice. Despite the beauty of your show tank, no one likes to walk into your living room and get a whiff of that “fishy” smell.

There is a lot of confusion about how activated carbon acts in saltwater, especially when it is used in reef aquariums. Here, aquarists are constantly pushing for a more natural filtration approach. But it bugs the hell out of me when I read all the misinformation on the Internet and even on carbon product labels. They preach to use carbon sparingly, like one day or three days a month, or don’t use it all. Folks, Activated Carbon is non-toxic. It cannot be overdosed. It will not remove all the salts and trace elements and turn your tank into some incomplete blend of synthetic seawater.

We all need to realize that our reef and fish-only aquariums are NOT miniature slices of the ocean. They may look that way, but bio-chemically they are an ecosystem that is always on the verge of collapse. Activated Carbon’s job is to remove metabolic wastes, or more commonly called organics. You can employ the deepest sand bed or the largest calcium reactor or a humongous circulation pump, but none of these things will have any effect on organics.

When it comes to organics, the world’s oceans maintain a perfect balance of metabolic waste removal through a series of natural recycling systems. Both the volume of water and the immense surface area provides a home for tens of thousands of species of macro and micro organisms that process these wastes. In the home aquarium, just a small fraction of these organisms can survive. Coupled with an extremely high specimen to water ratio, organics tend to accumulate in closed systems, and can reach concentrations orders of magnitude beyond natural ocean levels. Even with aggressive water changes, these organics can never be diluted enough to mimic the natural levels where our livestock has lived for thousands of years.

Don’t confuse organics with ammonia, nitrites, or nitrates. The bacteria responsible for breaking down these nutrients naturally thrive in all aquariums. Most tanks are nutrient rich and provide lots of food for these bacteria to thrive. Organics on the other hand, consists of complex metabolic compounds including phenols, organic acids, proteins, fats, carbohydrates, and hormones. To break these down, we don’t (and can’t) grow the right bacteria in our aquariums. In fact, detritus on the gravel surface and in the bottom of the sump are organic compounds that have reached such high concentrations that they fall out of solution. These particles remain inert as long as pH, oxygen, and ORP levels stay constant. Any wild swings or disruptions will trigger detritus particles to release these pollutants back into solution, causing an avalanche effect which will fuel a tank crash like there’s no tomorrow.

Where Do Organics Come From?

Creation of organics is a natural process of fish and invertebrate metabolism. It has little to do with the amount of food added to the tank. Reef tanks are especially vulnerable to organics, since corals and invertebrates produce a lot more organics than fish. Coral “slime” is nearly 100% pure organics. When you are mounting a coral or moving things around, copious amounts of sliming results. This slime is torn apart by powerheads, oozes through mechanical filters, and finally winds up being dissolved in the aquarium water. By contrast, coral slime in the ocean is quickly washed away perhaps hundreds of meters away from the coral. It is then consumed whole by other invertebrates or fish or quickly broken down by specialized bacteria and used by plankton as food. Everything is recycled in the ocean. In the aquarium, it has to be removed.

Why Organics Are Bad

While only a few of the organic compounds are directly toxic to marine livestock, they can stimulate the growth of heterotrophic bacteria which robs your tank of oxygen. These bacteria also create carbon dioxide. The result is lower pH and low ORP, which creates ideal conditions for nuisance algae to thrive. Organics can quickly tint aquarium water to a yellow color which greatly blocks blue spectrum light penetration (actinic 420nm). High levels of organics can also tax a protein skimmer to the point where nitrates and phosphate removal becomes minimal.

No one knows for sure the total make up of organic compounds in the marine aquarium and what specific effects they have on different organisms. It had been observed that aquariums with high organic levels experience more fish and coral diseases. There is now firm evidence that organics stunt fish growth. The old mystery of how a fish will grow only as large as its container has been solved. It has nothing to do with the volume of water or the size of the tank- organics accumulation is the culprit.

At moderate organic levels, corals and invertebrates tend to close or cease reproduction. Some researchers believe that there is a direct relationship between high levels of organics and dense populations of disease organisms. The reduction of naturally occurring organics ultimately leads to improved water quality and healthier specimens. Activated Carbon is the most effective and easiest method of removing organics from aquariums.

How to Tell if Your Organics Levels are High

The tell tale signs of high organics in marine aquariums include (1) Persistent hair algae problems despite low nutrient levels, (2) Some foaming in the sump or in the corners of the tank, (3) An oily film or cloudy layer on the water surface where even a tank overflow can’t seem to get rid of all of it, and (4) small growths of Cyanobacteria spotting on rocks and the gravel.

How Activated Carbon Works

Activated carbon is a unique product that starts out as nut shells, wood, or coal. It is pyrolysed in a 750°C oven which cracks the material and creates millions of micro pores on the surface and though the interior of each grain. The surface area of these pores are immense. One gram of granular activated carbon has 5,300 square feet of surface area. By comparison, a tennis court is 2,800 square feet. It is not only the large surface area of carbon that attracts organics, but there is an electrical charge involved that draws organics to the carbon.

Choosing Activated Carbon

In the aquarium trade, bulk activated carbon is sold in granular and extruded forms. Extruded products appear as pellets and spheres. These carbons are more rugged and can take tumbling in media reactors without breaking apart. They also tend to have less dust. However, extruded carbons have less surface area than granular carbons, so more product will be needed to achieve the same results. Granular carbons are softer and are more dusty. Dust level has nothing to do with the quality or effectiveness of carbon.

There are lots of brands of activated carbons to choose from. The quality ranges from downright detrimental to excellent. Avoid any product that uses the term “charcoal” or “char” in its name. These products are not activated and are limited to removing heavy metals and odors. There are ineffective against organics. They also contain calcium phosphates- which act as a nutrient for algae growth.

Activated Carbon has gotten a reputation of adding or leaching phosphates back into the water. This is only partially true. Activated Carbon can be made in two ways, either by Physical Activation or Chemical Activation. Physical activation used CO2, oxygen, or steam, and contains no phosphates. Chemical activation uses phosphoric acid and zinc for activation. If you buy the latter, then adding carbon will also add phosphates to your water. You are better off not using carbon at all then using a phosphate washed product.

Here’s a guide on what to look for when buying activated carbon:

► Look on the product label for information about the carbon. If the label talks about the carbon process of using steam, oxygen, or carbon dioxide, then it is truly phosphate-free and won’t leach phosphates into the water. Some carbons are simple marked “Phosphate-Free” which indicates a steam activated process. If the label does not mention phosphates, doesn’t tout the activation process, or requires rinsing to minimize phosphates, it is likely a low grade phosphor-washed carbon that should be avoided.

► If you use your carbon in a media reactor or tumbler, buy an extruded or pelletized carbon. It won’t break apart when the grains bang into each other. For use in canister filters or mesh bags, use granular carbon. It will give you more surface area- albeit at the cost of being softer and more fragile.

► Ash is an inorganic material that is left behind after the activation process. Look for carbon that is marked as low ash content or one that states “Does not affect PH”. High ash content can cause a significant rise in PH when first placed in the aquarium. This can cause undue stress on the livestock. I have personally seen pH values climb within minutes from 8.0 to 9.5 pH with some carbons. All carbons contain some ash and a thorough rinsing in fresh water will remove most of it.

► Quality brands of activated carbon will feature other parameters, such as Iodine Number below 600, Molasses Number above 400, or listing pore size in Angstroms. These are all signs of a quality manufacturer that has nothing to hide, and is offering a superb product.

How To use Activated Carbon

► For ongoing maintenance, I recommend 1 cup per 60 gallons of water. This is a bit higher than most suggestions, but using more carbon works faster and lasts longer. Double this amount for tanks with obvious signs of high organics or first time carbon use in poorly maintained tanks.

► Filter the water mechanically before it reaches the carbon. Particles greater than 100 microns in size will take a toll on the life of the carbon.

► Despite popular belief, carbon does not need to be placed in a canister filter or a compartment where all tank water passes through it. Dropping a mesh bag full of carbon into the sump works fine. This is because carbon works by electrically attracting particles- it is not an inert mechanical filter. Studies have shown that bags of carbon in a sump with moderate flow removes substantial quantities of organic pollutants, medications, and heavy metals. Actual performance depends on the flowability of the bag material. It is most effective if you use a media bag with the largest possible hole sizes but small enough where the carbon cannot escape.

► For the average marine fish aquarium, carbon will last 6 weeks. Reef tanks produce more organics than fish-only tanks, so 4-6 weeks is a workable limit. If the water is not mechanically filtered or the aquarium shows signs of nuisance algae, you will need to adjust the useful life or increase the amount of carbon.

► There is no effective way for the aquarist to either recharge carbon or measure its rate of exhaustion. I have experimented with the Salifert Organics Test Kit to measure carbon life, but I was unsuccessful because the range of the test kit would not allow me to measure steady declines over time. Don’t re-use carbon or try to clean it. Recharging carbon requires a specialized high temperature/low oxygen oven that would be prohibitively expensive at this small scale. The best solution is to replace the carbon at 4 to 6 week intervals.

Activated Carbon Myths and Misconceptions

► Carbon removes trace elements- Carbon has a greater affinity for organics than trace metals, but it will remove some trace elements. On the other hand, both protein skimming and natural consumption of trace elements by tank specimens will remove significantly more trace elements than carbon. Aquarists concerned about depleted trace elements should be using a trace mineral additive- whether or not carbon is used. Two excellent products for this are the Sera Strontium Complex and the Seachem Reef Trace products.

► Carbon will leach organics back into the water False. Once all the carbon pores are saturated, bacteria slime and detritus will accumulate on the carbon grains, turning it into a weak biological filter with the organics locked in the deeper layers.

► Carbon should be used only a few days a month False. This myth was likely started by activated carbon’s ability to remove yellow tinting and odor from the aquarium within the first 48 hours of application (or perhaps manufacturers who want to sell you more carbon). The higher concentrations of organics are colorless and odorless and require more contact time for removal. Another complication of part-time carbon use is storage and reuse. Once the carbon is removed from the aquarium it will continue removing contaminants from the air. Placing the damp carbon in a sealed plastic bag doesn’t work either, as the damp carbon becomes exhausted servicing die off in the stagnant aquarium water stuck to the grains.

► Spilled carbon causes harm to the aquarium False. Carbon granules that are accidentally spilled into the aquarium will quickly become saturated with bacteria slime, having the same biological effects as a grain of gravel. It may look ugly, but it is totally harmless.

As we have seen, the use of Activated Carbon is an important part of maintaining a healthy marine or reef aquarium. It is the only filtering media that can remove substantial amounts of metabolic wastes (organics), which accumulate over time and can prevent secondary water quality and health problems in specimens. Because of the phosphate issue in lower quality products, it is better to spend a little more on a quality carbon than use any carbon at all.

This is a follow up to my previous blog of November 2007 concerning nitrates. I presented an article all about Nitrates- where they come from and how to deal with them. I discussed deep sand beds, live rock, coil denitrators and chemical additives such as AZNO3. All of these methods (or a combination of them) can be effective in reducing nitrates in the aquarium. Nitrates are the number on cause of algae in marine and reef aquariums, and some form of algae control is mandatory for long term success.

But the problem with all these methods is that they require high maintenance by the aquarist on a continuous basis.. Deep sand beds need cleaning, Live rock needs to be “turkey-basted”, coil denitrators need to be fed, and chemical additives need to be dosed daily. Some people take the “after approach” of using snails or herbivorous fish to eat the algae that is caused by high nitrates. Same problem here: snails have short lifespans and need to be replaced frequently. Herbivorous fish may suddenly lose their taste for certain algae types with no apparent reason.

At the end of the orginal article I touched on a new method of nitrate control (new to the hobby, but used extensively in public aquariums). It is called the Sulfur Filter. It also goes by the names Nitrate Reactor, Sulfur Denitrator, or Sulfur Reactor. This device looks very promising because it is virtually maintenance free and is designed to remove large quantities of nitrates in a small footprint. Heavily loaded tanks with 100+ ppm of NO3 can easily be maintained at zero or unmeasurable levels.

When this article went to press back in November 2007, I has no personal experience with sulfur filters. Eric Edwards of Fins and Reefs (www.finsreef.com) saw the article and sent me a unit for testing. This particular model is an H&S 110SR, rated for use up to 250 gallons.

Before I get into my findings, let me explain how these things work. They look and work very similar to a calcium reactor, but require no CO2. The chamber is filled with pure elemental sulfur in the form of small bright yellow beads. The nitrate removal mechanism is called “Autotrophic Denitrification by Sulfur-Oxidizing Bacteria”. Now that’s a mouthful. The process though is quite simple.

The bacteria species that do all the work are Thiobacillus denitrificans and Thiomicrospira denitrificans. You don’t need to add this bacteria to start the filter. They are all over the planet and exist everywhere, including in your aquarium water.

Tank water is pumped into the bottom of the filter at a very slow rate, like 1 drop every 1-2 seconds. The water pushes upward through the sulfur beads and the oxygen is stripped out by bacteria. The higher up you go the less oxygen is present. The bacteria in the upper layers have no oxygen to use so in order to survive, they need to create it themselves. They do this by eating the sulfur and combining it with nitrates (and also nitrites, if present) which liberates an oxygen module for food and in turn, gets rid of the nitrate molecule. The water leaving at the top of the chamber is nitrate free.

There are some side effects to this process. Nitrogen gas is produced, which is no big deal as it just escapes out the top of the chamber. Carbon dioxide gas is also produced which is a big deal. The water leaving the chamber is very acidic and will lower your pH. To fix this, a layer of calcerous material (like crushed coral or aragonite gravel) is placed on top of the sulfur beads. This process also adds sulfates to the tank water, but the quantities are so low that an imbalance is unlikely.

All aquarium sulfur filters use a recirculating pump. This increases efficiency by passing tank water through the sulfur multiple times before it exits. Also, very little sulfur is consumed, so you won’t have the replace the sulfur media for 3-5 years.

This all sound wonderful, but does it really work? I had my doubts. Here’s what I found out.

I hooked the H&S 110R to a 125 gallon FOWLR tank. This aquarium has 12 large fish in it (around 3-7 inches long) and around 40 lbs of live rock. Nitrates have been as high as 50ppm, but due to aggressive skimming and regular water changes I was able to keep it down between 25 and 30 ppm, albeit with a lot of effort. The aquarium exhibited the usual algae signs for this level of nitrates- I need to clean the front glass 2-3 times a week, and tufts of hair algae appear from time to time here and there.

The directions that came with the sulfur filter said to start the drip rate at around 1 drop per second, and in two or three days check the nitrate level in the drip water. If it’s not zero or close to zero, then slow down the drip rate some more. Well, in 3 days the nitrates were 25 ppm, the same as the tank water. I did slow down the drip rate as slow as I could go, maybe one drop every 5 seconds. But the problem is these little airline valves are crappy. I’d wake up in the morning and it wasn’t dripping at all. I had to fiddle with it all the time.

I waited two weeks for the filter to cycle and checked nitrates again. The level was around 20 ppm. I tested both the drip output and the tank water and they both read the same. I couldn’t figure out why that would be. So I gave it another two weeks.

After running it to the end of the month, the nitrate was level was around 12 ppm. This thing is definitely working, but not the way I expected. Same deal on the nitrate testing- both tank and output drip read the same.

I let another month go by. Measured the output again. Still at 12ppm. Perhaps I reached the capacity of the unit- this is all it could handle. This aquarium gets the equivalent of 4 frozen fish cubes a day in food, so maybe it just can’t keep up with that. I kinda expected the break-in period for sulfur filters to be like cycling a new aquarium. You know, ammonia, then a continuing nitrite rise for a month, then a nose dive to zero. Not the case here.

When I hit 2 months the results were still the same. Maybe the nitrates dropped just a little to around 10 ppm (it’s hard to read the colored liquid against a printed paper color on these test kits). Anyway, I called Eric at FinsReef to talk about this. He was a bit surprised at how long it was taking, but emphasized that the H&S 110SR could easily handle my tank with room to spare. He told me that the cycling time runs differently on different aquariums. Tanks with higher initial nitrate levels seem to cycle faster. But sooner or later, they all kick-in. He suggested flushing the sulfur filter by running the output full open for a day. Perhaps some CO2 or other gases or contaminants were preventing the unit from fully working. Also, adding some vodka (1ml every two days per 75 – 125 gallons) will provide a carbon food source and speed the cycling.

I took his advice and did all of that. I also unplugged my UV sterilizer. Maybe the UV unit is killing all the bacteria in the water before it settles on the sulfur beads. Eric didn’t think the UV sterilzer would have any effect, but I unplugged it anyway.

Another week went by. Still the same results. At this point I convinced myself that this was as good as it gets. But not too shabby- I could never get nitrates down to 10 ppm using water changes and skimming alone. So I was satisfied, but certainly not a believer in all the hype on how well these filters work. I also used the last of my nitrate test kit chemicals, so rather than run out a get a new test kit, I felt that this experiment was over.

The following week things started to change. It was Wednesday and I didn’t need to clean the front glass of film alage. The gravel, which was always covered with a little bit of brown and green algae, had areas of white showing through. Over the next week, the entire gravel bed turned white and all the algae died. My hair algae was gone except for a patch stuck on a powerhead. I pulled that off with my fingers which left a bunch of short strands still attached. Within a few days, even those strands died off. My tank never looked better.

I still haven’t replaced my nitrate test kit but at this point, I felt I didn’t need to. I don’t care if nitrates are at zero, 10 or 20 ppm. The result I was looking for is there.

I really don’t know if turning off the UV unit, flushing the sulfur filter, or adding the vodka was the fix. Or perhaps it was none of these- it was going to take 3 months to cycle no matter what I screwed around with. I tend to believe the latter is what really happened here.

My recommendation? You’ve got to go out and get one of these for yourself. Forget about deep sand beds, deniballs, and nitrate removers. This is the way to go.

I didn’t test the sulfur filter on a reef tank yet, and I will probably do that in the next month. A reef tank normally has far less nitrates than a FOWLR, so the effects may not be as dramatic. But the biggest advantage I see of using one of these on a reef tank is getting away with more frequent feedings. If I could achieve daily feedings in my reef tank with little or no algae growth, then in my opinion, the sulfur filter is worth its weight in gold.