Opened the pool a few days ago and discovered a ring of dark spots around the whole pool about where the water level was at the closing, this level is just below the return lines in a roughly 4” thick band of spots. We got a ton of rain this winter so the water level was far above it almost immediately. The water level was probably about a foot above where this ring is most of the winter. There aren’t any spots near the water level that was maintained the whole winter (2-4” below tile)
Info about closing: pool builder did the close, shocked it and added stain and scale stuff, combat 60, and covered with mesh cover. It was closed very late in season, around Thanksgiving.
I’m worried it’s black algae, but it looks almost like it’s hairy and sticks out a bit. I can’t really find much info on what black algae looks like other than black spots. Initially thought just debris on the wall, but brushing doesn't seem to do much.
Pool had 0FC at open, pH was 8.7, TA 110, CH 270, cya 30 phosphates 300. Salinity was low and no one had salt available in the area to bring it up to use SWG, temp was a little low anyway. Pool guys dumped in roughly 5lbs shock, purple stuff and combat 60. Next day I could only get a 0.5 FC reading, was told it was too cold (58) and it would take a few days for the shock to properly dissolve and FC to rise. Waited 2 days but in the meantime worked on adjusting other levels. FC never rose above 0.5. I added liquid chlorine and was finally able to get salt, and get the swg going as water temp was about 61.
Current values are around 4FC, pH7.8 TA75, CH320, cya between 30-40.
I guess my questions are: Would black algae show up over winter in the northeast? Would it follow a ring around the pool at a water line that was there for a few weeks? And does it protrude from the surface, like bumps or even filaments?
My plan at the moment is to treat as if it was black algae and increase my FC to somewhere over 10 and maintain that for about a week and scrub 2-3 times a day.
Info about closing: pool builder did the close, shocked it and added stain and scale stuff, combat 60, and covered with mesh cover. It was closed very late in season, around Thanksgiving.
I’m worried it’s black algae, but it looks almost like it’s hairy and sticks out a bit. I can’t really find much info on what black algae looks like other than black spots. Initially thought just debris on the wall, but brushing doesn't seem to do much.
Pool had 0FC at open, pH was 8.7, TA 110, CH 270, cya 30 phosphates 300. Salinity was low and no one had salt available in the area to bring it up to use SWG, temp was a little low anyway. Pool guys dumped in roughly 5lbs shock, purple stuff and combat 60. Next day I could only get a 0.5 FC reading, was told it was too cold (58) and it would take a few days for the shock to properly dissolve and FC to rise. Waited 2 days but in the meantime worked on adjusting other levels. FC never rose above 0.5. I added liquid chlorine and was finally able to get salt, and get the swg going as water temp was about 61.
Current values are around 4FC, pH7.8 TA75, CH320, cya between 30-40.
I guess my questions are: Would black algae show up over winter in the northeast? Would it follow a ring around the pool at a water line that was there for a few weeks? And does it protrude from the surface, like bumps or even filaments?
My plan at the moment is to treat as if it was black algae and increase my FC to somewhere over 10 and maintain that for about a week and scrub 2-3 times a day.
