Hmm, interesting idea about burning, but wood ash is alkaline and still contains phosphorus....its hard to make that stuff go away but maybe less so than decaying plant matter.
I do notice that areas of my lake that are just clay dont have much weed growth, and seems to have shorter weeds - but I expect that might change as more materials decay and gather.
People have mentioned phosphorous binders and algaecides but i prefer to keep things more chemical free if i can.
When I had a bloom in the drought we just had I blasted water in from my upper swamp and it cleared the bloom right out and really cleaned up the water.
