This is my first post but have been reading posts and doing my own testing for a year now.
My problem is algae blooms that return with FC greater than 4. After a 12 inch rainstorm last year I started having some problems. When I got the pool ready to swim in April, I noted gray slimy material, which brushed away easily. I brought up to MSL and held for a few days. The next rain we had, the pool got cloudy even though the FC was 4 and found more of the gray slimy stuff and brushed it all, and opened the lights to clean out the nooks. Passed the OFCT and let it come back down.
We had rain last week and I immediately brought up to regular shock level. Still yesterday the filter pressure started climbing, and today I noted a little cloudiness, bur did not find any slimy material. The Pool chemistry this morning was:
I have already brought the FC up to 32. Any other suggestions?