I have yellow to dark brown stains on my vinyl liner. I lowered my pool water PH to 7.0, have no chlorine in the pool FC = 0 and added 1.5 lbs. ascorbic acid. Nothing happened.
Put roughly 2 cups ascorbic acid in a sock, dropped it in, nothing happened. Used brush to move around sock, nothing happened BUT the sock now has green stains on the outside.
24,000 Gallon rectangle pool.