Pond Boss Forums MANAGING AN EXISTING POND Fertilization Algae

With the presence of algae is it necessary to fertilize this year? Does the presence of algae necessarily mean that there is plankton bloom?

Bill - there are numerous types of algae, ranging from simple (phytoplankton) to advanced forms (chara).
I suspect that you're observing filamentous algae (stringy-slimmy mats), which can grow on the pond's bottom wherever sunlight is able to penetrate with sufficient intensity. As it matures, gas bubbles become trapped in its mass of filaments, prompting the mass to break free from the bottom and float to the surface - where it migrates wherever the wind takes it.
The purpose of a pond fertilization program is to promote a phytoplankton "bloom", which benefits the pond's food chain - but ALSO helps to reduce sunlight penetration, thereby reducing the amount of suitable habitat for filamentous algae growth.
Should you fertilize? Guess it depends upon the type of algae that presently occupies your pond.

Kelly, it sounds looks like the latter after your explanation so I will fertilize. I had bought some additional aluminum sulfate for one more treatment but will not do it until a later time if at all. My water has cleared approx. 12 to 18 inches and this is fine with me after seeing what real clear water tends to lead to. ie, Marshell Williams Also, I don't want the water too clear to make it more difficult for the birds to hunt on my shoreline. The water primrose is being controlled by a hard garden rake at present. Hope we can keep it that way. Thanks for you insight.

Bill- I can't say that I'd recommend fertilizing the pond if a filamentous algae "problem" already exists. The additon of nutrients at this time of the season could make the problem worse. Ideally, fertilization should be initiated earlier in the season (mid-60 water temps) so phytoplankton populations can get a jump-start, before filamentous algaes wake up from their wintertime nap. Maintain an existing bloom by incremental bumps of fertilizer - as needed. But proceed with caution if you have a fair amount of filamentous algea present.