Benefits Of Algae
  PondStuff! Monthly Pond & Water Gardening Newsletter



You might be surprised to find out that it is ALIVE and swims in the water. One type, Philodina, (a Rotifer which removes harmful bacteria in the pond) looks exactly like flukes, even being the same size! With the modern pond owners having such high-tech conveniences, such as state of the art microscopes, I can see how we can get ourselves into big trouble if we identify a parasite which is a plant and treat the pond accordingly, can even contribute to pond “crash” and dead fish. I already knew the koi’s worst enemy is its owner, but this brings us to a whole other level. The focus needs to be on the internal ecosystem of the pond, rather than any single threat. Algae, comprised of several types, are the “good guys” in the pond. Today you should be able to really understand the process of going from “new pond” to established ecosystem for the health of your koi. For instance, if Fluke tabs were to be used on Philodina, it would destroy the Philodina population and a short while later you would see Aeromonas as the koi’s immune system drops precipitously.

The basic types of Algae are Filamentous (the hated string algae which actually acts as a “nest” for beneficial bacteria to become established). It serves as an intricate support structure for your fish. It can be considered a “perennial” alga as it dies back in winter, except for the “holdfast” cells that secure it to rocks and other pond structures. It is from these holdfast cells that the new strings will emerge in spring. Cladaphora is the Blanketweed that NOBODY wants. This is a fairly new focus for many of us in the hobby, but all of us have fought against algae at one time or other. Many of us make a full-time pursuit of removing algae from our ponds. We have UV lights to destroy algae, but that would only be the next type of algae: the single-celled Planktonic algae. Although it serves a purpose and is not harmful to fish, it is unsightly and more commonly known as “pea soup algae.” A less known alga is Cyanobacteria (brown algae) and is not actually algae, but a bacterial colony which is most easily recognized as the brownish slime that grows on anything that is immersed in water for a while. (That’s the same stuff I have to clean out of my canary’s bath and water dishes!) Then there are Diatoms which cause brownish or cloudy pond water. And lastly, Mougeotia is the short velvet-green algae that grow on the rocks.

*Something you might not know- algae’s “food-of-choice” is ammonia! It absorbs nitrites, reduces nitrates and phosphates, and creates “structure” in the pond. When someone calls me for help with an algae problem I always ask them, “What color is the water?” It could be a problem with the filter instead of the pond itself. It could be a bloom of diatoms, particularly in colder water.

*Some of the negative aspects of algae in the pond are oxygen consumption by the algae during the night (or sunless days) causing acute hypoxia and dropping pH rapidly. If you test for pH at 7:00am and 4:00pm, you will see if the pH is stable. Algae can affect the pH and Alkalinity levels adversely when not producing oxygen. This can be especially harmful in August when water temperatures are usually highest and a power outage could then be disastrous as the oxygen levels drop quickly. The best emergency treatment at a time like this is to spray fresh cool water on the pond to cool it down and the addition of Sodium Bicarbonate. (Did you know that Long Island well water has a natural pH of 5?)

Some think the use of concrete will stabilize pH in the pond. However, it works briefly, until the algae covers the surface, and seals it. Concrete actually increases the variability of pond chemistry. It leaches hydroxide and the pH will be too high in a new pond. Calcium Hydroxide in our water supply doesn’t last long- we need some sort of carbon (carbonate, as in sodium bicarbonate). It isn’t the high pH that causes stress to fish. It is the fluctuation of high/low that is not tolerable. The Total Alkalinity may be the most important test kit to have in your cupboard.

- Carolyn Weise (information gained from the research of Dr. Julius Tepper, DVM)

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