Before you can get a good answer, you should do some more homework to find out which type of gnat that is causing your "gnat" problem. There are numerous types of "gnats" that live around ponds. Figure out which type of gnat that is causing you concern.
https://en.wikipedia.org/wiki/Gnat

When I was in graduate school I took a course titled Nematocera aka Gnats.

Last edited by Bill Cody; 06/12/24 09:35 PM.

aka Pond Doctor & Dr. Perca Read Pond Boss Magazine -
America's Journal of Pond Management