SWCG and Pool Coping

[rlanthony@excite.com]

I really want to get a SWCG but am concerned. I have mineral deposits on my coping from pool water wicking up into the coping. Thsi is not splash water but water being absorbed into the coping somehow. if I put a SWCG in the system will it leave salt deposits as well? Some people in our area have had the coping literally start to "rot" away form the salinity. What do yo think.
Rick
14100 gal IG pebble sheen.
Natural "Leuder" stone coping

[Jeffski]

My pool builder said that would happen and recommended not doing the SWG. I did it anyway. Too soon for results from me, but when I posed that question on this forum last year nobody else seemed concerned. SWG's are very popular and have been for years, and the reported cases of rotted copings apparently are few and far between.

[chem geek]

I would say that the answer depends on the coping (the type and quality of the stone) and that any coping that has signs of damage in a non-salt pool environment with typical salt levels of 500-1000 (an pool with a fresh fill and initial chemical additions has around 250 ppm) is probably going to see more or faster damage at the higher salt level of an SWG pool (around 3000 ppm). This can be mitigated through sealing of the stone.

You can do a water bead test for your stone. See how long a drop of water stays beaded up on the stone vs. getting spread and absorbed. If it's just a few minutes, then it's a very soft stone and will degrade rather quickly and should be sealed to prevent that. If it's 5-10 minutes then this is still somewhat soft. If it's 10-30 minutes, this is moderately hard, if it's 30-60 minutes this is a hard stone and more than an hour (if the water doesn't evaporate before then!) is a very hard stone that shouldn't need sealing at all.

There's a thread in the China Shop that explores this issue technically, but I don't want to scare you off from an SWG as most people are very happy with their systems. Stone naturally degrades and soft stone degrades faster so should generally be sealed and that is independent of the type of pool you have. We have textured concrete hardscape and concrete coping that we seal every year and our pool doesn't have an SWG.

Richard

[PatL34]

The only problem with the pool coping, is making sure when adding salt granules, that none are left on the coping. Wash down with a hose if necessary.

I have found that the salt interacts with the concrete over time to give a lump, which has to be chiselled off.

Pat

[rlanthony@excite.com]

Thanks for the reply. I can tell you without even testing the coping that it absorbs water immediately. Sometimes I wash the coping with a hose to remove dirt etc... and the water is absorbed right away. We have a pool builder in the area that sent letters to customers stating not to use their SWCG. He had a tremendous amount of coping failures. Someone said he used cheap stone or a "second cut" of stone. I don't buy the second cut line, but porous stone I can see doing that. How do you seal coping by the way. Since my CYA is over 100, I have to keep the chloirne levels about 8 to keep the algea at bay. It grows really fast here. I average 90 degrees in the summer. I know I should lower the CYA levels to keep less chlorine levels, but just haven't done that yet. I am not yet convinced I can get away with a SWCG, since I see the mineral deposits from the pool water leaching into the coping without any splash water. I saw somewhere on the forum something about a pool sealent that is put into the water and it seals the pool, plaster, tile grout, miny holes etc... any thought on that as well.
Rick