I have a vinly liner pool, 30,000 gallons.
My shallow end has developed a ton of light to dark brown stains that do not rub off.
I tried the Vitamin C test with no luck.
I then tried the trichlor puck test, left it on the bottom in a sock for about 15 minutes, and it cleared the stain up right below the puck just fine.
My FC and TC levels are in the normal range currently. My PH is a bit high, so I just put some muriatic acid in the pool to try to help that out.
I use liquid chlorine (12.5%) mainly and do not like to use the trichlor pucks as they introduce CYA slowly, of which mine has always been on the high side. The cheapo test strips tell me my CYA is "high" at around 150 or so.
Given that info, should I throw a ton of liquid chlorine at this staining problem to see if it will go away? I usually put about 4 gallons of the 12.5% in to keep the FC and TC levels steady, but I have a bunch so I could dump 10+ gallons in it if everyone thinks that's what I should do.
I hate these stains, they are very ugly and frustrating. Any help is greatly appreciated.