Ok, I thought I had this down, and now I'm stumped! Here's the situation in a nutshell...
Rainy and very little swimming this week, pulled back the solar cover and had some small areas of faint algae in the shady part of the deep end. Brushed it off.
Discovered the pump had been left to pull from the skimmer only, and the water was very high=poor circulation.
Have been using BBB all summer with much success, haven't had to shock yet.
Husband tested at 10 a.m. PH 8.2, FC 7.0 drop test, he didn't know to test for CC's.
Added acid in two steps to bring PH to 7.5.
I went to the store and loaded up on Bleach to go into Algae killing mode.
Tested at 1 p.m. and FC at 4 and CC at ZERO!!! Tested twice with same result.
Other numbers: TA: 110 CH:220 CYA: 30 plus a bit but not 35 WaterTemp: 81 Full Sun on pool today
Is the sun or the algae eating the chlorine?
Do I need to shock?
thanks as always for the help!