FC 2.5
CC 0.5
CH 250
TA 125
CYA 60
The pool water is clear no issues but have stubborn black algae spots which appears in two layers. The top "biofilm" layer is shiny which (steel) brushes off easy leaving the more stubborn layer underneath the shiny layer which is embedded into gunnite floors or walls. What is the alternative to attack the stubborn layer, as is at deep end 7.5 feet as the long pole / brush combination only seems to get the shiny layer off and otherwise cant hold me breath long enough to swim down and scrub by hand, any ideas appreciated. thanks
CC 0.5
CH 250
TA 125
CYA 60
The pool water is clear no issues but have stubborn black algae spots which appears in two layers. The top "biofilm" layer is shiny which (steel) brushes off easy leaving the more stubborn layer underneath the shiny layer which is embedded into gunnite floors or walls. What is the alternative to attack the stubborn layer, as is at deep end 7.5 feet as the long pole / brush combination only seems to get the shiny layer off and otherwise cant hold me breath long enough to swim down and scrub by hand, any ideas appreciated. thanks