SWG pools and natural stone decking corrosion...true/myth?

msg73

0
Sep 22, 2011
19
I'm looking to put in a new pool and different builders are saying different things about SWG pools and whether or not they will damage natural stone coping/decking. I'm looking at Tennessee Crab Orchard or Norwiegan Buff for the stonework and would like to also have the stone laid underwater in the benches and sun shelf.. Some say that the SWG will damage the stone and are asking me to sign a waiver and others are saying that SWG pool water is like sweat or tears and it won't damage the stone. What's the real truth? Thanks!
 
Re: SWG pools and natural stone decking corrosion...true/myt

The real truth is it depends on the stone. Softer stones will erode and flake with prolonged exposure to salt water. Do the ones who want you to sign a waiver require it for all salt water pools or just pools with specific types of stone work?
 
Re: SWG pools and natural stone decking corrosion...true/myt

Underwater shouldn't be as much of a problem. The issue with higher salt levels and stone has more to do with repeated splash-out and evaporation cycles that cause salt re-crystallization pressure. That's why areas with regular rains during the summer don't usually have this problem even when using softer stone. As you noted, the stone in the deck (splash-out) area can be sealed, if necessary.
 
Re: SWG pools and natural stone decking corrosion...true/myt

I have travertine (a limestone based stone) coping and I'm concerned about this as well. I sealed it well and after brushing the pool each week I hose down the coping and my decking with fresh water hoping to wash away any salt that would have evaporated. It's only been six months with my SWG but so far so good. I know some people, however, who say the SWG was the biggest mistake they made with their pool because they had to replace their natural stone coping in just a couple of years. I've also seen other salt pools that have waterfalls over flagstone and rocks with no problems at all.
 
Re: SWG pools and natural stone decking corrosion...true/myt

The builder didn't state type of stone in the SWG waiver. From my understanding, Tennessee Crab Orchard is a sandstone and is softer. Therefore, I'll probably go with Norwegian Buff as I believe it's quartz based stone. I assume it would hold up better than standstone. I also may consider the pop-up sprinkler heads to wash/cool the patio down automatically.
 
Re: SWG pools and natural stone decking corrosion...true/myt

My experience has been right along the lines that chem geek described. Salt recrystalization upon pool water evaporation over time will break the stone. If it has layers, the layers will separate. If it has cracks, they will get bigger. I have not see damage just due to the chemical composition. So, if you can keep the salt from forming crystals and breaking things, you'll be alright. If you can't, you'll have problems. Here in the desert, it will eat away at concrete because you can't rinse it off fast enough sometimes. Sealers and various paints stop that from happening.

Of course, then you have to maintain the sealer and paints.
 
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