Brown Pond Algae

Asked August 16, 2016, 9:19 PM EDT

Hello, I have a small (25'X 25') pond that is nearly opaque with what I think is a brown suspended algae. What should I do? I used a copper based algaecide one month ago to kill off green algae but now a brown type remains. Thanks Pat Walsh

Clinton County Pennsylvania

1 Response

A brown opaque appearance to water is usually either caused by suspended plankton (phytoplankton and/or zooplankton) or sediment. Sediment can be caused by fish in the pond or by runoff entering the pond. If the appearance is caused by plankton, a treatment with an algaecide should clear the pond. If it is sediment, the cause needs to be determined and fixed (i.e. fewer fish, redirecting runoff away from pond, etc.). Also keep in mind that, if this is plankton, it will disappear very quickly as we get some cold weather. We have more information on all of this at: