I've noticed small black spots forming on the walls of my pool. Brushing doesn't seem to affect them. Scraping with a fingernail breakes them up some but them seem to be embedded into the plaster some. Any thoughts what they might be?
The water has been clear and the chlorine has been maintained for several weeks now.
FC 10 (CYA ~80 LAST CHECK)
CC 0
pH 7.6
The water has been clear and the chlorine has been maintained for several weeks now.
FC 10 (CYA ~80 LAST CHECK)
CC 0
pH 7.6