It isn't really necessary to use algaecide. If you stay on top of your water chemistry, you really don't need it. I never use it. Some people use it only at closing in the fall. Some people do use maintenance doses of it. The only type we recommend is Polyquat 60%. More info here: http://www.poolsolutions.com/gd/polyquat.html

Phosphate solutions? Forget it. They are the latest thing pool stores use to remove money from your wallet. Don't need it.