Hair Algae And How To Control It

Mention the word algae to a marine aquarist and the first thought is usually ‘marine nightmare’. Hair algae usually meets this criteria. It is unloved and unwanted. Strange to think that in the very early days of the marine aquarium the aquarist would be pleased to see the algae growth as it would improve the water quality by feeding on nutrients. Under good lighting, the algae also produces a lot of oxygen. That was true and still is, but nowadays all the aquarist wants is rid of it, or at least the excess growth. There are better ways of maintaining water quality.

The [tag-tec]hair algae[/tag-tec] discussed here is also known as filamentous green algae. That is because it grows, if allowed, in large groups with long very thin and flexible ’leaves’. It is a hardy algae and can spread quite alarmingly, causing trouble in a reef aquarium and potentially in a fish only aquarium.

So how can this nuisance algae be controlled. ’Prevention is better than cure’ is a well known saying and without doubt it is applicable here.

This algae requires nutrients to prosper, as do all living things. The major nutrients that concern the aquarist are phosphate (PO4) and nitrate (NO3). A reef aquarium should have a nitrate level of 10 ppm (parts per million) or less, probably best as undetectable. Phosphate should be 0.03 ppm or less, preferably undetectable. The fish only aquarium should have levels as low as possible, though these may be inevitably higher because of a bigger bio-load, that is, more fish.

The obvious first move is to deny the algae the nutrients. It is a very good thing that from the very start the aquarist uses R/O ([tag-ice]reverse osmosis[/tag-ice]) water. This will ensure that the initial fill, routine water changes and make up water are as pure as possible. If the aquarium is already up and running, it is advisable to begin using R/O water for top-ups and routine water changes.

The aquarist may well state with justification that the aquarium filtration employed is live rock, and that will deal with nitrate. Correct, it will, if present in sufficient quantity and quality. However, all things have limits, and over feeding and/or overloading the bio-filtration will result in nutrients.

A major source of nutrients is feeding, particularly with beginners. Feeding the fish is a most enjoyable task, and at the same time the aquarist is concerned that the fish have enough. There is a danger that excess food will enter the seawater and it will not be consumed. It will break down and nitrate will appear. Phosphate also is mainly introduced with food. Prepared marine flakes are not specially processed and do produce nutrients despite the early and incorrect assumptions of some new aquarists. It is clear that feeding should be a disciplined affair, enough being fed but without excess. Fish can consume enough food, but their instinct is to ‘grab it while its there’, and some food can pass through the gut semi digested.

If the aquarist finds that the nitrate and/or phosphate level is higher than desired and has critically examined the feeding discipline, is sure the bio-filtration is not overloaded, and is carrying out routine water changes, then there are further means to assist in dealing with the algae. One or a combination may be effective.

Nutrient Reduction By Filter.

Phosphate can be reduced by using an anti-phosphate resin in a filter, often called a reactor. The phosphate is absorbed and is therefore removed from the seawater. Nitrate can be reduced by use of a filter where certain media is used and kept in a very low oxygen condition. Bacteria extract oxygen from the nitrate and break it down.

Nutrient Reduction By Sump.

A sump can be used to house a [tag-self]deep sand bed[/tag-self] (DSB) which will act as a filter, and in addition the macro-algae Caulerpa can be grown in the sump. The Caulerpa will use nitrate and phosphate itself and thus compete with the filamentous algae. When there is sufficient Caulerpa the filamentous algae will be starved of nutrients.

There is another way to deal with the nuisance algae. The nutrient levels should be reduced as far as is possible, but the hardy hairy stuff may persist! If this is the case, then lets use the algae as a food.

Predation By Fish.

The aquarist can introduce certain types of fish to eat the algae. Theoretically, an equilibrium could be obtained, the fish eating the algae, producing nutrients, and the algae re-growing to be eaten again. This is more difficult than it sounds. The aquarist must beware of overloading the bio-filtration and overcrowding the aquarium. Any algae eating fish should be introduced slowly, one at a time, and regard given to their eventual size and compatibility with current livestock. Two types of fish that could be of use are the surgeon fish and rabbit fish families. The latter are generally more hardy.

Predation By Snails, Urchins, and Hermit crabs.

These are very useful in the struggle with nuisance algae. In this topic, the algae is the filamentous type and it is clearly very important to properly research the life forms to ensure that they will in fact eat the algae type. Again, although there is less of a concern with overloading the bio-filtration, introduce them slowly and observe the affect on the algae. More can always be introduced. If too many are introduced initially, then the excess are going to die, definitely not wanted.

So there are ways to battle the nuisance filamentous algae. Nutrient level control is always the first thing to achieve. Then other considerations can be given. The algae seems to be able to hang on despite the loss of food, but it will slowly reduce. If full control cannot be achieved, then using it as a food source for fish etc is another option.

Finally, that requirement of all marine aquarists should be mentioned – patience!

Hair Algae And How To Control It
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  1. For ponds, and aquariums – Microbelift
    I just thought I would share with those of you having algae problems. First of all, I am not selling product, I just want to rave. I have tried EVERY method, EVERY product to contain my algae. I rent my house, and I have a 350 gallon koi pond. I’ve salted it, ive netted it, I use clarifier, algaecide, barley extract,you name it. The next thing I knew, my pond was; again, filled with so much algae I couldn’t see my three little koi fish. Then it got worse, and took over the sides of my pond and was all over my pump. I have no idea what kind of algae, it was green and fuzzy. Anyhow, after adjusting the PH, rinsing my filter, reseasoning it with good bacteria, all that stuff you are suppose to do, it was still green. I had spent like 80.00 all together on product. I went to this local, hole-in-the-wall place and she told me to try Microbelift. It was 26.00. I didn’t want to buy it, but she said, it smells dreadful, but your pond will be clear in three days. (I had heard this before) It has everything in it, it kills the algae, puts benficial bacterias.. Everything, so you only have to buy one product. It is safe for fish. I bought it, went straight home and put it in my pond, (I almost threw up from the smell). My pond was clear in four days. I haven’t touched it since, and my fish (who I can now see again) are still alive. I will never use anything else, and I can live with 26.00 for 6 months of product, rather than 80 every three. You could also use this in your aquarium. Good Luck!!!

  2. Thanks for that Gieshadoll.
    It sounds like green hair algae. Glad that your persistence paid off!

    I would like to repeat, if I may, that chemical additions to combat algae should be the last resort in my opinion. I speak of marine aquariums of any type, not of ponds, though I suspect that the same would apply.

  3. There are some other factors, that you can control, that benefits the algae growth and you can decrease or reduce.
    As the excesive ligthing ( or to much long photoperiod ) and temperature ( to warm benefits the algae growth.


  4. Good point Victor. Algae requires light and too much could cause problems. However, there still needs to be sufficient nutrient presence for the algae too prosper.
    .-= John´s last blog ..Aggression On The Reef =-.

  5. Nice post. I agree with you on the “prevention is better than cure”. It really lessens the work and headache. I also apply the nutrient reduction thing which is great. What I do is I ‘starve’ the algae by not giving it enough nutrients and sunlight. I do that by planting various plants around it so there is competition. Another thing I do is to keep the water running or circulating. Algae usually grows when the water becomes a bit stagnant so if the water is continuously moving around there’s a smaller chance for algae growth. Barley straw extract also works out great since it naturally adds beneficial enzymes, lowers the pH and creates peroxide which can kill both filamentous and planktonic algae.

  6. Thanks for that Scot, interesting and helpful.

  7. Great and informative post about saltwater aquarium. Thanks for sharing and keep posting!

  8. Hi All.
    I’ve been experimenting with my pond to eliminate hair algae. Using algae control chemicals caused nitrite levels to rise which resulted in more frequent water changes. The bottom line, easiest way to eliminate it is to add more oxygen to your pond! It’s that simple!!! I thought my waterfall and spout from the skimmer were enough to oxygenate my 1300 gallon pond, but I was wrong. I bought two small air pads and set them on bottom of 4′ pond and add 1/2 teaspoon of beneficial bacteria (Aquascape powder) once weekly. No more am I battling hair algae! Also, if you don’t have a skimmer, get one. You will be surprised how much algae that skims out of your pond. I have my waterfall hooked up to one pump and the skimmer to another

  9. Hello Trish, thanks for calling. Though this website is about marine aquariums your comment is interesting. Just goes to show that some careful thought and very careful experimenting (provided the person has reasonable experience) can be beneficial.

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