Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Copper sulphate

RAH, what do you you recommend for FA control?

https://aquaplant.tamu.edu/management-options/filamentous-algae/

Diquat (Rated: Good)
Alkylamine Salts of Endothall (Rated: Good)
Flumioxazin (Rated: Good)
Sodium Carbonate Peroxyhydrate (Rated: Good)

I personally control it in my ponds by managing nutrients through a healthy population of plants. Copper fungicides work well but can accumulate in soils.

I've had a bad experience with Alkylamine Salts of Endothall (Hydrothol 191). It does kill fish, and I lost fish in my hatchery pond. They started floating within a few hours.

If the water is void of fish, or shallow enough that small fish aren't swimming in the problematic area, then it does work well. I did use up my bag of Hydrothol, but I was very selective of where I used it.

Got to stay under 0.3 ppm. https://aquaplant.tamu.edu/files/2018/08/Hydrothol-191-Label.pdf

I'm not even gonna check that. If you posted it, I know it's correct. So, be extra careful with Alkylamine Salts of Endothall, and do your math. It's the only herbicide/algaecide that caused me problems. I would also consider going with liquids if possible. The fish I lost were in the granular fall zone, and no fish were killed adjacent to that. If I could have seen those fish, I would have gone a different route.

Thank you for your confidence, but its always good to check advice. We do have some really knowledgeable folks here that challenge dogma (and some outdated university extension recommendations) which is why I have a nice YP/SMB pond.