Another Article On Algae Control

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jhnrb

Reef enthusiast
Algae Control

There is no holy grail for algae control in our aquariums. Algae needs three things to live; water, light and food. To control unwanted algae we must remove one of the three elements. Since we are keeping aquatic life forms it is probably not a good idea to remove the water. Since algae control is primarily of interest to reef aquarists, it would not behoove us to remove light. So that leaves food.

What is food for algae? The primary food for algae is CO2. Chlorophyll in the algae uses energy from the light source to convert CO2 into a simple sugar, such as glucose, that in a nutshell is photosynthesis. Algae also benefit from other nutrients common to our aquariums as well; phosphate, nitrate, silicate and sulfate are the top four. There are many ways to import these foods into our aquaria, use of tap water for top off and water changes. Overfeeding, use of substrate and rock high in phosphate or silicate content.

Whatever the source, we must attempt to limit the nutrients from our systems. This can be accomplished through the use of RO/DI water for top off and water changes, use of kalkwasser (lime water) for top off (precipitates phosphates), use of protein skimmer to remove dissolved organic compounds. Employment of a deep sand bed to remove nitrates, the fauna in the sand will eat the detritus that settles on the sand bed. The anoxic areas of the sand bed will consume nitrates converting them to nitrogen. (CAUTION IS NEEDED HERE ON THE DEPTH OF THE SAND BED. COVERED UNDER A SEPERATE ARTICLE TO COME).

The use of animals to remove the food as well as algae itself is recommended. Herbivorous fish such as tangs have an indispensable place in our reefs, as well as grazing snails (astrea, nassarius {not a grazing snail, but benificial} and trochus) and chitons. Small hermit crabs can also be used to scavenge uneaten food.

Aquascaping is also important in algae control, as well as water flow. A tight wall of rock up the back of the aquarium will create dead areas of water flow allowing detritus to settle and become a sight for algae growth. A loose arrangement with good water flow around, under, behind and in front of the rocks will serve our purposes much better. This also has the benefit of requiring less rock = less money. We should strive for water flow that intricate and moves great volumes of water. This will keep detritus in suspension to be eaten by our corals and scavengers or removed to the protein skimmer for manual removal.

Following are a few types of algae and some things that can be done to eradicate them if they bloom.

-Cyanobacteria (red slime algae)

Cyanobacteria are really photosynthetic bacteria. Typically it is deep red in color, but is also found in green and blue-green. It forms slimy sheets on aquarium surfaces, rocks and substrates. Cyanobacter will also trap air bubbles under the sheet. This algae is caused by excess nutrients in the system. Treatment is problematic at times; some will recommend the use of antibiotics. This will work, but does not address the underlying problem, the excess nutrients. Siphon out as much as possible; perform a water changes using RO/DI water, increase protein skimming, cut back on the amount of food or the frequency of feedings and use a fresh saturated solution of kalkwasser for top off.

-Diatoms (dusty, rust colored)

Diatoms are probably the most common form of algae found in aquariums. Every new aquarist finds diatoms in their tank at the end of their cycle. Diatoms are easily controlled through the use of grazing snails. If you find a bloom check out your silicates, as they are incorporated into this algae's shell. These algae can also be hindered through the use of RO/DI water for make up water.

-Hair Algae

Hair algae are very common pest algae in reef aquaria. The most common cause of hair algae is phosphates and nitrates. (Note: if you use a municipal water supply, phosphate is added to your water by federal mandate, to combat lead piping in old houses) Removal of hair algae can be difficult and time consuming. First; manually remove as much as possible, water change with RO/DI water, reduce the import of phosphates into your system. If you are using a trickle filter or other conventional biological filtration, remove the media. Reduce mechanical filtration, increase protein skimming and maintain high alkalinity. Use herbivorous fish such as the yellow tang to eat the unwanted algae. If it is persistent a reduced photoperiod may be in order.

-Dinoflagellates (brown slime, snot algae)

Dinoflagellates are closely related to the endosymbiotic algae in our inverts; zooxanthellae. It is called snot algae because it has the consistency of nasal mucus; it is transparent to brown in color. It lays down stringy sheets, similar to Cyanobacteria, which trap air bubbles in their tissue. This is a very dangerous alga because it has the ability to quickly remove oxygen from your system. It has also been hypothesized that the algae is toxic to herbivorous fish and snails. The treatment is much the same as Cyanobacteria, with an addition, try to keep your ph elevated above 8.6 during the day and above 8.3 at night and you should see it crash pretty quickly. One good thing about this alga is that it is pretty rare.

-Valonia spp.

The dreaded bubble algae. These algae have fascinated and frustrated reef aquarists for many years. The real problem with them is they are so darn pretty. If not allowed to over run the tank they can be very interesting indeed. Removal is recommended as soon as they are noticed in the tank, they have the ability to spread very rapidly and encroach on our sessile invertebrates. Removal is simple; use forceps or needle nose pliers and pull them off, preferably without bursting them.
 
Unwanted Algae

Dealing with Unwanted Algae in Marine Aquariums

by: James W. Fatherree, M.Sc.

For many hobbyists, unwanted algal growth in aquariums can be a real nuisance. But, keeping it under control isn't so difficult if you know what to do. Whether it is fine microalgae growing all over the glass panes, on rocks and decorations, or on top of the gravel/sand substrate, using the right tools, techniques, and helpers can make things far less frustrating, and keep your aquarium looking its best. So, let's go over some of the things you need to know to keep it at bay.

Regardless of what type(s) of alga you find growing in your aquarium, keep in mind it isn't so different from "regular" plants when it comes to basic requirements. They all need light and they all need nutrients. In addition, there is probably something that likes to eat them, too. Thus, we need to look at each of these and see how they apply to control.

Lighting first. If you have a non-reef/fish-only aquarium with no light-dependent livestock, you can simply leave the lights off as much as possible. Like I said, algae need light, so if it is showing up, just try keeping the lights on for a shorter period every day. I usually advise hobbyists to leave the lights on from the time they get home from school or work until they go to bed - but not all day while they aren't at there. Also, if your aquarium receives a great deal of sunlight where it is located and you think this is spurring growth, you can get some good window blinds/curtains, or move the tank to a darker area. The fishes will get some ambient light in most any room, and they don't seem to mind being in the shade for most of the day. Depending on how long the lights do stay on and how much other light the tank gets, this can make a huge difference in how your aquarium looks without having to do anything else at all.

Conversely, if you own a reef aquarium, you're obviously stuck with having very intense lights that have to burn for several hours a day to keep the things alive that you want to keep alive. There's not much you can do about that without interfering with the health of any sorts of symbiotic corals and such in the aquarium. Thus, you'll obviously have to rely on other means of control.

Of course, even if you can keep lighting to a minimum, that isn't always enough. You'll also need to maintain good water quality to help, as the nutrients that algae need are found dissolved in the water itself. When it comes to these nutrients, it is phosphorus in various forms that is the prime fuel for growth. Phosphorous makes up part of any sort of fish or invertebrate food that you add to an aquarium, and it also makes up a large portion of most any plant fertilizer. So, as you can imagine, it is essential to keep concentrations at a minimum.

To start, it is very important that you make sure not to over-feed the animals in your aquarium. Common advice is to refrain from adding more food than your fishes can eat in one to three minutes, but I tend to look at the fishes and not my watch, and feed them until they seem happy. Note that I do this by giving a little food, and a little more, and a little more until they are okay, rather than dumping in one big load at once. How much and how long you feed will be up to you and your own judgment, of course, but the important thing is to make sure that they don't leave any leftovers. The same applies for any sort of invertebrate foods, etc. that reef aquarists may be using. Any leftover food that doesn't get eaten by something somewhere in the aquarium will break down and increase the concentration of phosphorous in the water. Do keep your senses about it though and realize that starving your fishes to death to quell an algae problem is not the way to go about it.

With that said, the fish will nevertheless eventually release all of the food you did give them in a different form. We tend to think if it as waste, but it still has phosphorus in it, too. Once fish waste is in the water or on the bottom we call it detritus, and keeping detritus from accumulating is the next goal. For everyone that uses some sort of mechanical filtration, like a sponge or floss filter, it is imperative that you clean it out regularly. Pull the filtering media out as often as possible and rinse it out thoroughly. This will keep detritus from building up in the media and thus keep it from slowly releasing phosphorus back into the aquarium. Letting such a filter run for long periods may help keep the water clear, but it isn't going to do anything to help keep algae away.

Using a good skimmer (foam fractionator) can help to maintain excellent water quality and help to keep phosphorus concentrations down, as well. The nasty sludge that builds up in a skimmer's collection cup is comprised of all sorts of junk, and is also rich in phosphorus. So again, the nutrient is being removed from the aquarium instead of building up in it.

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Next, using a specialized phosphorus-removing product can also help. These products are appropriately called "phosphate removers" and they'll extract some phosphorous-based compounds from the water. When enough is used they can have such a dramatic effect on phosphorus concentrations that I've used them in aquariums that literally had green water and seen them clear up completely in a couple of days. But, such products shouldn't be thought of as a "magic bullet" that will fix everything and allow you to dump phosphorus in your tank at will. They only remove certain types of phosphorus-based compounds, not all of them, and they tend to be rather costly, as well. In addition, many hobbyists have reported that the use of phosphate removers that contain aluminum can have strongly adverse effects on a variety of soft corals. This has recently been tested and verified experimentally*, so if you choose to use such a product and you see problems with soft corals, remove the stuff immediately and find a brand that is aluminum-free.

Last, but certainly not least, you can (and definitely should) perform periodic partial water changes, using purified water. I strongly recommend doing water changes to improve water quality, using phosphorous-free water produced through reverse osmosis filtration or distillation. Each time you use purified water to make up synthetic seawater and add it to an aquarium, you'll be diluting whatever phosphorous there is and thus lowering the overall concentration. The more water you change, the more the concentration goes down.

Now, with these tools and techniques covered, we can look at some living organisms that can help out. For starters, you can use other types of algae as competitors and as a means of phosphorus removal. Secondly, a large number of sea creatures make their living by eating algae, and they'll be quite pleased to do the same in your aquarium.

You may be able to keep a variety of attractive macroalgae, such as Caulerpa, growing in your aquarium. The macroalgae will use the available phosphorous like any other algae, and will incorporate it into its own living tissues. Thus, as is it grows, more and more phosphorous will be taken up. As it continues to grow, you can then pluck out clumps and strands here and there to keep it under control and in doing so will be physically removing nutrients from the system. The macroalgae suck up the phosphorous, you pull out some of the macroalgae. It's that easy. The only problem is that you'll need sufficient lighting (as in reef-type lighting) to keep it growing well.

If you don't like the idea of having a bunch of macroalgae growing in your beautiful reef tank, you can always grow it in a second tank hooked up to the main one. Such tanks are often called refugiums or an algal scrubbers, and they can hold the macroalgae out of sight under the main tank, or can be used as an additional display tank for other types of critters. Many people have chosen to use algal scrubbers as a primary means of aquarium filtration, so if this sounds like the way to go for you, I strongly suggest you do some further homework on the topic.

As far as using algae-eating animals goes, herbivorous fishes can be invaluable. Surgeonfishes (tangs) are a popular choice, as they will nibble around the tank all day. Most will pick at microalgae on the glass and the rocks/decorations day and night. Personally, I absolutely love algae-eating blennies, too, and don't think red-lipped blennies (Ophioblennius atlanticus) and lawnmower blennies (Salarias fasciatus) can be beat. They have big mouths and stay busy, and like many other blennies, both have unique personalities. Even though they aren't the most beautiful fish around, you'll enjoy watching them and they'll help earn their keep at the same time. Really, there are entirely too many algae-eating fishes to list off, but tangs and these blennies are indeed some of the best.

There are also quite a few crabs that will go after unwanted algae. Emerald crabs (Mithrax/Mithraculus spp.) are great at picking filamentous/hair algae, and some will even eat bubble algae (Valonia spp.). The only problem you may have with these is that some get big enough to knock stuff over. And, while I've never seen it myself, I've heard that big ones can grab fishes and make an occasional switch to being carnivorous. So, you may have a small one for a while and then find the need to pull it out later.

The same goes for the Sally Lightfoot/spray crab (Percnon gibbesi). They also make great algae eaters when small, but may get big enough to try to eat your fishes. I once read about one that liked to climb up onto rock perches and jump out at fishes when they swam close enough to be grabbed! However, I think this is exceptionally unusual, as I've never seen one bother anything at all (except algae).

Small hermit crabs can be great, too. The blue-legged (Clibanarius tricolor) and red-legged/scarlet hermits (Paguristes cadenati and Calcinus spp.) are at the top of the list, all of which will safely pick away at various sorts of algae found growing on the surface of live rock, gravel, and other decorations. These guys are also small enough in size that they won't knock anything over, or bother any of the other invertebrates either.

If you've got plenty of algae growing on the rocks you can always try a herbivorous sea urchin, too. Several common varieties are great cleaners which strip away tracts of algae, but note that they can pose a couple of problems though. First, they are typically covered with long, sharp spines, which can spear anything they happen to come across, including your hand. I haven't had any problems with them sticking any other critters, but I have had the misfortune of accidentally bumping an urchin on more than one occasion. Quite painful, indeed. And, they also have a specialized grinding apparatus for collecting food that works so well that they can grind patches of your live rock or decorations into sand. Any desirable, colorful coralline algae present may be stripped right away during the process. In a big tank with plenty of rock this may not even be noticeable, but in smaller tanks it can be irritating to see your rock, etc. slowly being chewed away.

Lastly, we get to the ever-popular algae eating snails. Turbo snails (Turbo spp.), astraea snails (Astraea spp.), and trochus snails (Trochus spp.) are the most common varieties, which will crawl all over and clean up every surface in a tank. If you should catch one moving across the glass you can even see its strange little mouth moving in a side-to-side pattern, slurping it clean and leaving a signature feeding trail behind. One thing to mention though is that of the three I have found that the larger turbo snails are not necessarily the most desirable of the bunch because they can get big enough that they may knock things around pretty badly at times. Astraea and trochus snails on the other hand, stay much smaller and are thus less likely to cause any problems.

That's about it though. So, now you need to think about how you can use any or all of these different tools, techniques, and creatures to fight any algal problems you may have. Just remember that no matter what you do, unfortunately, you'll probably still have at least some unwanted algae showing up here and there. But, that's just a part of having an aquarium.

Reference:
Holmes-Farley, Randy, 2003. Aluminum in the Reef Aquarium. Advanced Aquarium Magazine: http://www.advancedaquarist.com/issues/july2003/chem.htm
 
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