Need the expert help here. This is a SWG pool. It is seen above water line and appearing in more area slowly. Tried rub it with the trichlor puck for about a minute but no help.
The pool was built last year. Tested the water with metal but none found. Will try Vitamin c tablet as soon as I find any. Pool was always clear.
CYA 25-- adding more now
Thank you for any suggestion, advices!