You know, I think there is a lot of this stuff in the air or rain this year. It seems as if the pool stores are doing a good trade in algaecide...Every time I go in, there are scores of folks looking to get rid of mustard algae. Last year I had NO algae whatsoever. This year, another outbreak when we got back from vacation (no one to treat pool while we were gone). But not bad.

So now I know I have to keep the cl level quite high and run that filter 24/7. And get a decent testing kit.

This is a great forum.