FNC I kill any FA back with Cutrine. The process I use in my 3ac pond is to Kill back FA and then Fertilize with adding pond dye. The Pond dye keeps stuff from growing at depths for me. I curreently have 5 grass carp per acre to help combat any other growth the pond dye does not halt. I will remove some bigger grass carp when FA is not a problem as the year goes along. I then add small grass carp back in the winter to replace what I remove. I use pond dye thru most of the year as a management tool. If I see a spot of FA coming on pretty strong I will mix in a gallon sprayer a little of Cutrine and treat that small area also. Pretty much every year here I have to do things a little different because of the changes in annual climates. I take a more proactive approach.