Pond Boss Forums GENERAL QUESTIONS Help New alge in 50 year old pond.

Looks like you've got a serious crop of FA (filamentous algae). Depending on how you want to attack it, there are a couple ways to try to get it under control.

Algaecide will kill it, but you cant treat it all at once because it will deplete the DO as it dies and could kill fish if you treat the whole pond at once.

There is also a product called greenclean that will take care of it and is supposed to be safe for fish. Dont know a lot about it.

Then there is pond dye. You're already behind the curve on it controlling the algae but it may help knock it back some. It will also help reduce the other submerged plants by reducing the amount of sunlight that gets to the bottom. It really should be added in late winter/early spring to really keep it from becoming a problem.

Finally, there's aeration. By aerating the pond you add DO to the water which is supposed to keep algae from growing, but it may hurt that chrystal clear look you're used to by stirring up the bottom.

As old as the pond is, you may have built up a nutrient load that is more than the other grasses can use up, so the FA is stepping in to do its part. It grows on the bottom, then as it dies, gas bubbles get trapped in the hairs and causes it to float.

Hope this helps some. I'm sure someone else will pipe in as well.