Attached are pics of the bottom drain. It appears the vinyl liner is wrinkling around the drain making it difficult to clean. Don't want to scrub to hard as I don't want to crack a wrinkle thus cutting the liner. This has been there for a few years but slowly getting worse
-pool liner 11 yrs old
-I use liquid cl as for chlorine treatment. Started using liquid cl during the last 5 years.
-One person stated this was caused by large amount of liquid chlorine settling on the bottom before it disperses. Another person stated that Alkalinity was low at some time earlier.
How to clean until I replace the liner?