Here's a dumb question...are the different colors of algae indicative of an actual different type of algae? In our area, I've seen all different algae colors, including a yucky brown, that appears to be the same species or type.

I can't discern any different types by feel either. It all feels bad.

If rain water really drives out oxygen causing the algae to disappear (or whatever cause rain water exerts on the algae), then why wouldn't a water hose sprayed on an algae mat get rid of it? I don't know, maybe it would...someone should try that. That may be a simple solution to many folks problems. Anybody ever tried that?