I'm losing this battle with what appears to be very stubborn green algae that is stuck to the bottom of the plaster pool. I can brush some of it away but most of it is VERY VERY stubborn. A steel brush helps a little but it's also spreading everywhere. I came home from a month long vacation to find it's gotten much worse. It was being fed by tabs for a month.
In the center of the picture is after I brushed off what's loose on the bottom. Most of it is not coming off. The dark green stuff on the side is NOT coming off.
Prior to that I've been using store bought liquid chlorine. In the summer months it was mostly ok. But I noticed the green stuff getting more and more stubborn. Shocking it didn't get rid of the green stain last I tried, as you can see it's gotten very bad.
And the readings were:
CYA~60 (Probably more now since I used some tabs)
I'm in California and it's been very cold/rainy in the past month.
I need help to get rid of this stuff. What is it? Why doesn't it brush off?? HELP!!!