I have 1/2ac pond, stocked 8lbs of TP last yr and didn't seem to make a dent in the FA. This yr I stocked 20lbs in April, 4-6". At the time I had maybe 5% or less coverage of floating FA. As of today I've got 35-40% coverage. Granted I have a problem maintaining water levels and have lots of shallow areas 2-3 feet so I know that contributes to FA growth, just thought the TP would be able to manage it. Not the case. Not sure what I'll do for next yr.