Thanks Essuph, I have a 1/2 ac pond. Stocked it last year (Apr 2015) with 8 lbs of moz tilapia, it was my first year with the pond so didn't have anything to compare too, but the FA covered about 15% surface through the summer. This April I stocked 20lbs of same 3-6" TP,. currently have about 5% surface coverage. I'm starting to see more FA float to the surface. I'm hoping the TP will control it. If not I may consider the chemicals.
