The BioGuard Back Up product uses ADBAC algaecide, a linear quat that can foam, and others have found that to be successful at killing the bugs, but not dissuading them from coming. I suspect that 50 ppm Borates would have a similar effect because I suspect that lowering the surface tension of the water prevents the bugs from staying on the surface and/or creating an air bubble to breathe.
Certainly if you figure out what can keep the bugs from coming to the water in the first place, be sure to let us know so we can help others.
Certainly if you figure out what can keep the bugs from coming to the water in the first place, be sure to let us know so we can help others.