Recently bought some cutrine plus granular. I treated somewhere between 1/4 to 1/3 of my pond already and it looks to be working a lot better than the spray I was using. Algae is brown and disintegrating after about 3 days now. How long before I can treat another section? And is it okay to rake the dead algae out or should I just leave it and wait? I can still see some of the grains on top and hate to take them out if they are still working or is what’s left already used up?