dustmote4b
03-04-2007, 07:49 PM
I have a vinyl 25,000 gallon oval inground pool in Pensacola, FL. In the deep end side wall, I have an irregular shaped 1' X 3' grayish-colored stained area. The spot will not scrub off but disappears after I shock with liquid chlorine.... for a week or so and it returns again. For a while, I considered it a useful "early warning system" until a second spot appeared several months later about the same size. Any ideas on what the stains are and how to get rid of them? Thanks