Needs resurfacing

[newpooler]

I have a strange problem with a pool at a house I just bought. I live in Florida and the home was built in 1981 so it's probably Markasite.

When the pool is dry, we emptied it for repairs, the walls look white but when the walls get wet, brown patches appear all over.

Any idea what could be causing this before I resurface it with Diamond Brite?

Thanks.

 

[jblizzle]

Are the patches rough? Could be some calcium scaling that is more obvious when wet.