I am getting a black stain on the 3 discharge jets, 2 wide mouth skimmers, and now the 2 screened returns in the deep end.
My readings for the pool are:
Fc - 9
pH - 7.8
TA - 70
CH - ~100
CYA - 65
Salt - 3200
I noticed this last season and it was very mild compared to this season.
I don't know what could be causing this or how to address this issue.
A friend advised I have the SWG cell cleaned but I doubt that would do it.
Any advice would be appreciated .