JB,
A couple of years back I tried to rake out the algae in my pond (150'x 65'x 10') with mixed results. It helped to clean up some but I didn't achieve the results I was looking for. Never tried chemicals. I had a pretty good growth of algae going up till monday night. Our area was smacked with a torrential downpour and by days light, the pond was as clean as could be. My guess is the rain "flushed" the pond. I'm curious to see how long it takes to reappear.

Russ