We are currently fighting black algae in our white plaster pool. Have been shocking it at FC 35+ along with brushing with a SS brush.
We've had some rain and it dropped our CH level a bit from 190 to 150. I'm not sure if I should increase the CH level or not. In the past on the board I was told that my CH level was fine when it was at 190 but the recommended levels for plaster pools are much higher (250 - 300). I'm assuming 150 is enough of a drop that I should raise the CH level.
Should I raise the CH to 250 or just back up to around 190?
17,000 IG White Plaster Cart Filter Jet Vac Sweep new pumps and filter system this year; pool re-plastered 18 months ago
pH 7.8 (not accurate given high FC levels)