Very quick intro: I've owned the house since 2000 and the previous owner built the pool in 1995. In-ground, surrounded by sawn limestone coping and flagstone deck. We've been running a SWG since 2008 or so, and starting around 2012/2013 we noticed pitting and some crumbling occurring with the limestone surrounding the pool. It's not all of the blocks, but about half of them. The stone crumbles and leaves sand in the pool.
We are at a point where the pool needs some expected work. The plaster is original and needs replacement, and the limestone surround needs replacement also.
I see in the New Construction subforum that many folks have SWGs with all that beautiful rock. How is that rock protected from salt water? Is the popular moss rock and travertine mostly immune or is there a sealer PBs use to protect it?