Mystery of the Green Hair Algae

23 Jun, 2008

Not long ago I was standing at the counter in my favorite coffee house. As I stood anticipating my hazelnut latte, a green haired girl approached the counter. The girl placed her order with the barista and glanced down the bar to where I stood.

“Oh, Hi Carl!” she suddenly exclaimed.

If you’ve ever experienced one of those moments when someone greets you by name but you have no idea who they are, you have an idea of how I was feeling. I had no clue who this girl was, and I was reasonably sure I did not know anyone with green hair. To make matters worse, she started walking over to where I was standing.

Think, think, think. . . No, I am positive I do not know anyone with green hair.

By now, the girl had begun a conversation with me and it became immediately obvious that she must know me fairly well. Inevitably, the conversation reached a point where I could no longer fake it. The girl looked and me and smiled. “You have no idea who I am, do you?” she asked.

Don’t Recognize Your Former Aquarium?

When all goes wrong: reef smothered in hair algae.

When all goes wrong: reef smothered in hair algae.

Now I am going to go out on a limb and suppose that you might have had a very similar experience. Oh, maybe not a failure to recognize a girl with green hair, but perhaps you went into your living room one morning and found you did not recognize your marine aquarium? Perhaps because a watery habitat with copious green hair stood where your once pristine tank used to be? Hmmm?

If this has happened to you, you have come to the right place because here is the magic cure!

Just kidding, there is no magic cure. If there were, I would not need to write this article. And while I am on the subject, the first thing you should take away is that there is no magic cure for green hair algae. So please don’t waste your money on some remedy the guy at the pet store claims is going to kill your hair algae.

Generally speaking, green hair is in your tank because of a series of problems, not one single issue. Strong lighting alone will not cause green hair, nor will high nutrient levels. On the other hand, strong light AND high nutrient levels just might. Then there is the question of where the nutrients are coming from and what nutrients are involved. It’s a complicated topic because not all of you will have the same root causes and the “cure” will be somewhat different for each of you as well.

So where do we start on this complex subject of hair algae? I think I will start with something my old Taekwondo teacher used to say (I suspect he lifted it from a movie line): “The best way to avoid a punch is not to be there.”

Well, the best way to deal with hair algae is never to get it in the first place. This sounds simplistic but it is indeed my best advice on the topic of hair algae. I will therefore dedicate the remainder of Part I to techniques for the avoidance of hair algae. Then, in Part Two, we will tackle what to do if you are among the unfortunate aquarists who already have a hair problem and need to be rid of it.

Avoiding Hair Algae From The Beginning

Step one: Let us begin with the most obvious part of our aquaria; the water. It makes little sense to me to spend a fortune on equipment for an aquarium and then ignore the main ingredient. Your selection and processing of the source water for your aquarium is a primary concern. Your local tap water could be a significant source of nutrients including phosphates, silicates, nitrates and ammonia. I recommend every aquarist test his or her tap water regularly. I also strongly recommend processing the tap water with reverse osmosis (RO) and de-ionization (DI). Such pre-processing of the source water should be done not only for the initial fill but for all water that will ever be put into the aquarium. Combined RO/DI units are available just about everywhere and compared to the cost of the aquarium, filtration, lighting, inhabitants, etc, they are relatively inexpensive. Step one, then, in the avoidance of hair algae is always pre-process your source water with RO/DI.

Step two is to select a quality synthetic sea salt mix. The mix should be phosphate and nitrate free. It should also be chemically very close to natural sea water. I have no intention of getting into the “Who has the best salt” debate. There are many high quality synthetic sea salts on the market today … there are a lot of bad ones too. Do some homework. Talk to local aquarium clubs or advanced hobbyists. You will soon find out which salts produce the best results, in the experience of those you have questioned. Personally, I use Red Sea-brand salt. My reasons are that I like the way it mixes and my fish and corals do well with it. What more can I ask?

Step three in my green hair avoidance technique is a simple one but requires a certain amount of discipline. Age your seawater prior to adding it to the aquarium. I always mix my seawater at least three days prior to using it but I’d say mixing your seawater at least 24 hours in advance would be a good rule of thumb to follow. Freshly mixed seawater can have detrimental effects on your aquarium when added immediately after mixing. The salts are harsh and the gasses are not balanced.

I mix my synthetic sea salts in a fifty gallon, round bottomed, food grade container. I use only RO/DI water to mix with the salt. Inside the container are two submersible pumps. One circulates the water around the bottom of the container. The second pumps the water up from the bottom of the container and up and out of the top of the container via a rigid tube. At the top of the rigid tube is a “J-shape” which aims the water back down at the container where it runs into the top of the container like a faucet. This circulates the water from bottom to top and also provides good gas exchange at the surface. I also have a small submersible heater in the mixing container so that my freshly mixed water will be the same temperature as my tank water.

Step four continues to be about the water itself. Perform regular partial water changes. Even in the most meticulously maintained aquaria, waste products build up and essential elements are depleted or removed. Regular partial water changes help to reduce waste materials and replenish needed elements.

Step five is to provide open architecture to your decorating scheme. Water should be able to flow freely around your rock or other decoration to prevent pockets of detritus or waste buildup.

The last step is a series of things not to do to avoid hair algae problems:

  1. Don’t overcrowd you aquarium.
  2. Don’t overfeed your aquarium.
  3. Don’t overuse additives and supplements.
  4. Don’t use liquid invertebrate foods or liquid green water mixes unless you KNOW you have an invertebrate that needs it and then only if you specifically target that animal with small targeted feedings.

All of the above contribute to higher nutrient levels and a greater likelihood of getting hair algae.

Ok, but what if you are not among the wise and fortunate who are reading this prior to setting up their aquarium?

In Part Two, we will explore how to get rid of the stuff once you have it. (And see the tank shown above after its rescue.)

Oh, the green haired girl? She turned out to be an old friend. I just did not recognize her with her freshly dyed green hair. Much as you will not recognize your once pristine marine aquarium after green hair has moved in and set up house.

See: The Mystery of the Green Hair Algae – Part II

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About the author

Carl DelFavero
Carl DelFavero

Carl DelFavero is the author of Aquarium Keeping and Rescue

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