Well I have been lowering my TA level with acid.Due to 420ppm refill water
My current tests.
FC 4.6 , had it up to 6ppm earlier in the day-8 30 pm right now
shocked pool up to 20ppm 2 weeks ago. after refill from winter lowering
used polyquat 60 when closing pool but nothing since opening.
I started aerating yesterday morning with a fairly large water pump, almost like a small sump pump for the last 24 hours.
Never had this brown/black ring at water level line, most of it is at the opposite side of pool from where the pump is running.
Not sure but seems to even have some light liner fade at the water line at the far end of pool , maybe a inch tall in a small section.
After I added the acid, no more than a quart at a time, about 3 hours apart twice a day I would also brush the whole pool and have pool pump running and the aerate pump running- sudden freak out at sunset.
No one has used pool yet.First time i used this pump to get this much water bubbles.
Maybe too much? does make a lot of current also.The stain is a little hard too see with the crappy iphone, starting to get dark, and I did scrub some already with brush, and magic eraser, did get most off but still a slight dark sticky texture that just wants to smear like an old adhesive, I can scratch it with finger nail but tough to get off
My skimmer is near the pump I put in so maybe the the water isn't getting into the filter to circulate the chlorine? just guessing now.One thing I have done different this year.
I opened my pool and got everything running about 2 weeks ago, last week I installed a timer and had my pool pump running 8 hrs. from 10am - 6pm
Ran it 24/7 before.