Eliminating Green Hair Algae…

Pete Giwojna

Eliminating Green Hair Algae…

In my experience, the best way to get rid of the green hair algae (Derbesia) once and for all is to maintain optimum water quality at all times, Lora, which it sounds like you have been doing very well, at least for the water quality parameters that you monitor.

But to rid your tank of green hair algae, it’s very important to keep the phosphates at zero and the nitrates as close to zero as possible, and maintain the proper levels of pH, carbonate hardness/alkalinity, and calcium. If you can do that, the hair algae typically cannot thrive and will eventually disappear as suddenly as it appeared, but having a good cleanup crew with members that include hair algae on their menu will also be very helpful in that regard.

In most cases, you can eliminate the hair algae from your aquarium with a three-step process. The first step is to get the phosphate and nitrate levels in the aquarium down to zero. The second step is to make sure that the pH, carbonate hardness/total alkalinity, and the calcium and magnesium levels are in the proper range. And the third step is to physically remove as much of the hair algae as possible as often as possible and to make sure that your cleanup crew includes plenty of scavengers that like to eat the hair algae.

Let’s discuss how to accomplish the three steps above in a little more detail below, Lora.

Very often, high levels of nitrate or phosphate are present in aquariums with excessive hair algae growth, and seahorses will begin to experience distress when the nitrates rise above 20 ppm.

Getting the nitrates and phosphates in your aquarium down to zero will help immensely in getting rid of the hair algae, Lora, but in stubborn cases that may not be enough.

In that case, Lora, you should also concentrate on adjusting the pH, carbonate hardness, magnesium, and calcium levels in the aquarium. If you can maintain the total alkalinity/carbonate hardness and magnesium and calcium at the high levels recommended for reef tanks and keep your pH in the proper range, the hair algae will often disappear on its own.

You may need some additional test kits and supplements to add to the aquarium to achieve the desired levels of phosphate, magnesium, calcium, and carbonate hardness, Lora, but that should certainly take care of your hair algae problem in an instance where it is growing despite a lack of nitrate or phosphate to fuel its growth. Here is some more information explaining the proper range to maintain your water chemistry in these areas:

Natural Seawater Value = 2.5 meq/L
Acceptable Range = 2.5 to 5.0 meq/L
Optimum Level = 2.5 milliequivalents per litre (meq/L)is best for fish tanks; > 3.0 meq/L but < 5.0 meq/L is recommend for reef tanks. The alkalinity is basically a measure of the capability of your aquarium water to resist changes in pH from the addition of acid (Trevor-Jones, Nov. 2002). Acid is continually entering the aquarium, primarily as the result of respiration (CO2) and metabolic wastes produced by the aquarium inhabitants (Trevor-Jones, Nov. 2002). The addition of these acids tends to lower the pH of the aquarium water. The higher the alkalinity of your aquarium water, the more resistant it is to such downward pH shifts (Trevor-Jones, Nov. 2002). The amount of buffers (primarily carbonate and bicarbonate) in saltwater determines the alkalinity, so the alkalinity in effect is the buffering capacity (Trevor-Jones, Nov. 2002). When the buffering capacity of the water is depleted, the pH becomes unstable. A fluctuating alkalinity will lead to serious problems in maintaining an appropriate pH, as well as problems keeping calcium and magnesium levels within required ranges. Alkalinity test kits can now warn of low buffering levels in time to prevent potential pH problems (Trevor-Jones, Nov. 2002). Carbonate Hardness (KH): Natural Seawater Value = 7 dKH Optimum Level = 7dKH (for seahorses) Carbonate hardness is another measurement of alkalinity. It is usually expressed in the German unit dKH (degrees of carbonate hardness) and is often considered to be the total alkalinity. (Dividing dKH by 2.8 will give you the alkalinity in meq/L.) KH is actually a measurement of various carbonates and bicarbonates of calcium and magnesium within the aquarium water (Webber, 2004). Maintaining a stable KH is very desirable since it maintains the buffering capacity (i.e., alkalinity) of the system and prevents subsequent drops in pH. Aside from stabilizing the pH, reef keepers need to maintain KH and high alkalinity in order to assure that the calcifying organisms in the tank flourish. For this reason, although 7dKH is excellent for a seahorse only setup, or a tank with seahorses and a few hand-picked soft corals, aquariums with stony corals, calcareous macroalgae, or a lot of coralline algae can benefit from a somewhat higher KH reading. A good brand of artificial sea salt for a reef tank will yield a KH between 8-12 after being freshly mixed, in order to allow for the calcification that will occur once the water change is made. Corals and other calcifying organisms actively use bicarbonate, which is the main component of alkalinity, so the alkalinity of a tank with a lot of calcification can drop quite rapidly. However, you do not want the KH in the aquarium to rise above 13dKH for any length of time since KH readings in the 14-15 range and above can cause calcium to begin to precipitate out of the water, making it increasingly difficult to maintain an adequate calcium level in the aquarium... Calcium (Ca): Natural Seawater Value = 400 mg/L Acceptable Range = 350 to 450 mg/L Optimum Level = 350 - 400 mg/L (up to 500 mg/L in well-stocked reef tanks) Calcium is a very important element in the water in any marine aquarium and is a vital element in reef tanks. Along with carbonates and bicarbonates, it is required by calcifying organisms such as stony corals, snails and other mollusks, coralline, Halimeda and other calcareous algae, and certain sponges (Trevor-Jones, Apr. 2003). Calcium is a critical parameter for coral growth in reef aquariums, and chronically low levels will cause coral mortality and loss of coralline algae and other invertebrate species. Calcium reserves must therefore be replenished on a regular basis. Regular water changes may achieve this, but reef keepers may require the addition of biologically available calcium to maintain adequate levels (Trevor-Jones, Apr. 2003). Seahorse keepers should be aware that brooding males provide calcium to the developing fry in their pouches, which the embryos probably incorporate into their skeletons. Deficiencies in calcium could thus adversely affect your seahorses’ reproductive success and the health of the fry. In fact, seahorses that receive a diet deficient in calcium often suffer from decalcification of their exoskeleton, a debilitating condition commonly known as “soft plate” disease (Greco, 2004). Magnesium (Mg): Natural Seawater Value = 1280 mg/L Acceptable Range = 1100 to 1400 mg/L Optimum Level = ~1280 mg/L Magnesium is a key component of the water buffering system, and is incorporated into coral skeletons as the corals grow. It also plays a vital role in all photosynthetic processes. Low levels of magnesium indicate the need for more frequent partial water changes and/or buffering of the aquarium. In short, Lora, I would get test kits for total alkalinity and/or carbonate hardness, plus calcium and magnesium test kits, and adjust those levels as indicated above. The appearance of the hair algae suggests that you may have excess nitrates and phosphates in the tank, Lora, and the first thing you'll want to do in order to get this problem under control is to make sure your water quality is up to snuff, as we discussed previously. You'll want to make sure that you have as close to zero nitrates and zero phosphates as possible, and you'll want to make sure that the pH, total alkalinity, and calcium levels in the aquarium are at the right level. Many times nitrates and phosphates enter the aquarium in tap water, so you'll want to switch to RO/DI water if you have been relying on tap water when mixing up saltwater for your seahorse tank, Lora. If you can make sure your water quality is optimum, with as little nitrate and phosphate as possible, and the pH, alkalinity, and calcium levels within the normal range, then manually removing as much of the hair algae as possible on a daily basis and maintaining plenty of herbivores in your cleanup crew that include hair algae in their diet will eventually allow you to clear it from your tank. But you have to be careful when removing hair algae from your tank, Lora, because it can spread by fragmentation. I recommend using the method described in the following article for manually removing the green hair algae:
Green Hair Algae: Why me?!


Green Hair Algae (abbreviated as GHA for this article) – Derbesia – is a form of algae that looks like its name. It is usually dark green, grows quite long if left unattended and spreads across your tank rapidly. Once this problem has begun, it can get out of hand in a matter of weeks. And soon you start to look at your tank in disgust, thinking “Why me? What did I do to deserve this plague?”

A number of things may have contributed to it getting a foothold in your system. Your nitrates might be too high, your phosphates may be too high (.03 or less is the goal), your lighting has recently been replaced or perhaps your bulbs are so old that the spectrum of light has shifted, fueling algae growth.

First things first. You need to get your water parameters to Natural Sea Water levels:
pH 8.0 – 8.3
Ammonia 0
Nitrites 0 hope
Nitrates 10ppm or less
Alkalinity 8 – 11dKH
Specific Gravity 1.026
Calcium 400 – 450
Phosphate .03 or less

A lot of these are affected by the water quality you use before you even begin to mix your saltwater. If you use tap water, you might be adding nitrates or phosphates to your tank on a daily or weekly basis. RO/DI water is your best and most pure option. If your phosphates are high, you can use products like Kent’s Phosphate Sponge (white granules) that fit in a filter area that will reduce them from 2.0 to .2 in 48 hours.

Okay, so your water is great. To get rid of the algae, you are going to have to prune it back manually. Fortunately, you can get some help from ocean dwellers, but like anything, when you have too much of something, you have to get radical to bring it within manageable levels. Nothing good ever happens quickly, right? This is going to take some specific attention on your part for a few weeks, but you can overcome it.

Get a container of fresh water (tap is fine) and put it near your tank. I like to have it on the top edge of the tank. If you can clip it to keep it in place, even better. Reach into your tank, and pinch off a clump of the stuff. Pull your hand out still pinching the GHA so none of it gets released into your tank, and dip/rinse your fingers off in the water. Repeat this a hundred times.

The reason you rinse your hand after each pinch is to prevent the filaments from floating around in your tank and reattaching elsewhere, just spreading your problem further!

When your hand gets tired, switch to the other hand. Take your container and dump it out, rinse it well and put more water in it and get back to work. Try to remove as much as you can see and reach, working at this daily. By ripping it out in bulk, you prevent it from spreading, and you give your hermit crabs and snails something they can actually keep up with. Buy more snails to help with the battle. I prefer Turbo snails.

Whenever you see a snail that is not working on the GHA, pull it off the glass/powerhead/plumbing and put it on an area of algae. They work for you.

Clean your skimmer completely. Clean the pump/powerhead thoroughly, make sure your air intake is clear. Clean your collection cup often, so you don’t have slime buildup hindering it. You want to skim out as much of the Dissolved Organic Compounds (DOCs) before they can break down in your tank and add to the A-N-N cycle. Remember nitrates fuel algae growth. You want 10ppm or less to avoid feeding GHA. If your skimmer is underpowered for your tank, seriously consider upgrading to a better unit.

If you’ll keep up with this process for a few weeks, you’ll see less and less in your tank, until one day, your tank is pristine again. If you come to visit, you’ll see my little reef is cured, but it did take time and effort.

Okay, Lora, those are some tips that should be very helpful in eradicating the nuisance algae from your aquarium, including the stubborn hair algae. Here are some more suggestions that you may find helpful in that regard.

The hobbyist should also be aware that dead spots and low flow areas, as well as low pH levels, favor the growth of nuisance algae rather than coralline or macroalgae and marine plants. Eliminating dead spots and stabilizing your pH at 8.2 – 8.4 can therefore help tip the balance back in the favor of macros and coralline algae, and help prevent problems with nuisance algae.

One simple measure that can thus make a big difference is to try positioning one or more small powerheads so that they increase the circulation in the area where the nuisance algae tends to grow. Better water movement and higher oxygen levels will naturally tend to minimize the growth of slime algae and hair algae in these problem areas. Just be sure to shield or screen off the intakes for the powerheads so that a curious seahorse won’t get its tail injured by the impeller.

In summary, some of the measures that will help control nitrates and phosphates (and excess nutrients in general), or otherwise help control nuisance algae in the aquarium are the following:

1) Make sure your protein skimmer is working correctly. A protein skimmer works 24 hours a day to remove excess waste and nutrients from a tank. If the venturi is clogged on a venturi skimmer or there is another problem with other skimmer designs, waste will not be exported from your tank and algae will take advantage of the waste. In order to function efficiently, the protein skimmer must be cleaned regularly, including inside the cylinder where the bubble column forms to provide the foam fractionation.

2) Perform regular water changes. Regular water changes will decrease the level of wastes and nutrients in the water. But the water changes won’t do much good if your tap water itself contains phosphates and amines. Depending on how high the nitrate levels become, increasing the proportion of water that you change each time may be necessary to help reduce those nitrates. There is an article about nitrate reduction at <<<http://www.about.com/>>> in the saltwater section that really explains water changes (gives you the math), on actually how little you are reducing nitrates with small water changes when you have high nitrates.

3) Make sure makeup water is pure. Phosphates and nitrates are often found in tap water. Phosphate and nitrate test kits will show if your tap water is contributing to your algae problem. If phosphate and nitrate levels are more than 0 ppm (some tap water measures out at over 50 ppm nitrate), filter the water through a RO/DI unit before using it as makeup freshwater or as source water for saltwater changes, or purchase RO water from a vendor.

4) Add additional detritivores to your cleanup crew. If excess food isn’t eaten, it will decay and add to the nutrients and waste in the tank, as will the steady accumulation of detritus and mulm in an aquarium. More microhermit crabs, Nassarius snails and cleaner shrimp will help ferret out any uneaten Mysis and clean up detritus before it breaks down and enters the nitrogen cycle to eventually end up as excess nitrate.

So if you’re having a problem with nuisance algae, consider bolstering your cleanup crew with additional snails and/or micro-hermit crabs that eat slime algae and other types of nuisance algae. Astrea snails, red foot moon snails, and Scarlet reef hermit crabs (Paguristes cadenati) all fit the bill and would be good additions in that regard.

Under the circumstances, Lora, the first thing that I would suggest trying is biological control in the form of additional aquarium janitors that have a special fondness for Cyanobacteria and hair algae. I recommend augmenting the cleanup crew for your seahorse tank with scavengers that specifically like to feed on the cyanobacteria or red slime algae, Lora. Especially good for this are the Banded Trochus Snails and Tiger Sand Conchs that are available from Aquacon (http://www.aquacon.com/snails.html) and the Mexican Red Leg Hermit Crabs (Clibanarius digueti) and certain Cerith snails (i.e., Cerithium strercusmuscarum), which you can get from GARF at the following website (just copy the following URL and paste it in your Web browser and then press “Enter,” Lora — that will take you directly to the right site):


They cost just a few dollars apiece and I would recommend getting one Tiger Sand Conch plus a good half-dozen Banded Trochus Snails and one or two of the Mexican Red Leg Hermits plus a handful of the Cerithium strercusmuscarum snails, depending on how severe the problem with the slime algae and hair algae has become. (However, you should not need any of the Live Sand Activator.)

So it would make good sense to bolster your cleanup crew with additional snails and/or micro-hermit crabs that eat red slime algae and green hair algae. Astrea snails, red foot moon snails, and Scarlet reef hermit crabs (Paguristes cadenati) or other seahorse-safe scavengers that all fit the bill and would be good additions in that regard.

Introduced as soon as possible to a new aquarium, as soon as the ammonia and nitrite levels are safe, Astrea snails effectively limit the development of all microalgae. In other words, they are good at eating diatoms, but will consume red slime and green hair algae as well. The Scarlet Reef Hermit Crab (Paguristes cadenati) is a colorful micro-hermit that’s a harmless herbivore. So cannibalism isn’t a concern at all for these fellows, nor are they likely to develop a taste for escargot. As hermits go, most of the time the Scarlet Reefs are perfect little gentleman and attractive to boot. I even use them in my dwarf seahorse tanks. Best of all, they eat all kinds of algae, including nuisance algae such as red, green and brown slimes, as well as green hair algae.

And, as we’ve already discussed, Mexican Red Leg Hermit Crabs (Clibanarius digueti) and certain Cerith snails really like to eat cyanobacteria or red slime algae. Garf (http://www.garf.org/redslime.html) offers a Reef Janitors package with hermits (chibanarius or clibanarious digueti, mexican dwarf hermit) and the snail (Cerithium strercusmuscarum), which are said to do an excellent job of cleaning up red slime algae.

5) Introduce macroalgae to consume excess nutrients and nitrates. If regular pruning is done, fast-growing Caulerpa will maintain its color and high growth rates without going sexual. Better yet, an algal filter or “algae scrubber” can be established in a sump or refugium.

6) Chemical controls. Phosphate absorbers (e.g., Phos-Zorb) Can remove excess phosphates, and Poly Filter pads can help absorb excess nitrates, changing color as they do so, which helps indicate= when the Poly Filter needs to be changed. Low ash activated carbon that is free of phosphates will also help remove such nutrients if it is change religiously and replaced with new carbon.

7) Controlled addition of food to tank. Don’t broadcast feed, scattering Mysis throughout the tank. Instead, target feed your seahorses or use a feeding station. Don’t overfeed, cleanup leftovers promptly, and observe fast days religiously. Thoroughly rinse your frozen Mysis before enriching it, since these shrimp juices that accumulate when the Mysis thaws can be rocket fuel for nuisance algae.

It is especially important for seahorse keepers to rinse the excess shrimp juice from the frozen Mysis you prepare before you feed it to the seahorses, and as long as it’s just a quick rinse then it really doesn’t matter if it’s RO water or saltwater from the tank or even ordinary tap water that you use to gently rinse it. But that could rinse of the thawed frozen Mysis can pay big benefits for the home hobbyist by removing excess shrimp juice before the Mysis is fed to the seahorses because those shrimp juices are like rocket fuel for nuisance algae, stimulating rapid growth of hair algae or cyanobacteria (red slime algae).

8) Eliminate dead spots and increase the water flow in areas where the nuisance algae tends to grow.

9) Maintain the pH, calcium levels, and alkalinity of the aquarium in the proper range. Monitor alkalinity or carbonate hardness and the calcium levels in the tank as well as the pH.

10) Replace your aquarium lamps regularly to assure that the spectrum of light they put out favors the growth of coralline algae and macroalgae. (Over time, as bulbs age, they begin to put out light shifted more towards the red-end of the spectrum, which encourages the growth of hair algae.)

11) Reduce the photoperiod in your aquarium is much as possible to cut down on the light that’s available for photosynthesis.

12) Increase the circulation in the aquarium to eliminate dead spots, particularly in the areas where the red slime algae or hair algae tends to grow.

13) Physically remove as much of the nuisance algae as possible. Some aquarists go as far as to remove all of the live rock from the aquarium and painstakingly scrub it free of the hair algae or even boil it to rid it of the nuisance algae, but boiling it also destroys the beneficial nitrifying and denitrifying bacteria it houses.

Okay, Lora, those are some additional suggestions to keep in mind whenever you are dealing with an outbreak of nuisance algae. I know that you are probably already well aware of most of the suggestions and that all of them may not apply to your seahorse tank, but they may give you an idea or two that can help.

For more information, check out the following online articles which are loaded with additional tips and suggestions for controlling outbreaks of nuisance algae. Please read these carefully, since they’ll give you many more good ideas for combating your problem with hair algae:



Click here: GreenAlgContFAQs

Click here: Reeftank.com – Articles – Reeftank Maintenance – Algae Control FAQ

in addition to the URLs with useful information on controlling green hair algae listed above, Lora, I will also attach a document to this email which includes a comprehensive list of all the water quality parameters that marine aquarists should monitor in order to maintain optimum water quality at all times, including why they are important and how to adjust them upwards or downwards as necessary. Please download this document, save it on your computer, and then read through the information at your convenience.

Best of luck eliminating the green hair algae from your seahorse tank once and for all, Lora.

Pete Giwojna, Ocean Rider Tech Support

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