You're right about the salt water contributing to the deterioration of the stone. Admittedly, I'm not a "stone guy" but I have been taking care of swimming pools for years and I've seen it first hand. My salt pools with stone decks and/or coping have all needed to be sealed. They definitely take a beating from everything they are exposed to but, from what I've seen, you can solve the problem by sealing the stone. I've done it with success. I guess they can charge what they do because it's cheaper than the alternatives
Maybe the other sealers are cheaper, I've never checked. The Deck-O-Seal works for me and my customers so I stick with it.
On more than one occasion I've heard the manufacturers of the salt chlorine generators mention the degradation of stone and it has been written about in many industry trade magazines. The real question is that, outside the US, the pools in Europe and Australia are almost exclusively salt so, do they have these problems and, if so, how are they treating them? I wish I knew.
