We went on vacation a few weeks ago and there was a dust storm while we were gone. I adjusted the chemicals as the pH had gone up to 8.2 and the chlorine was almost undetectable. The infloor cleaning system seemed to have cleaned the pool pretty well for the most part except for the few normal spots that it misses. Once I finally got wet I noticed that the plaster felt gritty. I figured it was the outside layer of plaster finally shedding off to reveal the quartz underneath. So I didn't really think anything of it. The next day I decided to manually sweep the spots that the infloor hadn't reached, but the dust wouldn't move. At first I thought maybe it was a form of algae since the chlorine had dipped so low, but upon closer inspection I noticed that it was actually grains of sand that had basically glued itself to the plaster. It isn't actually only in a few spots, but the entire pool, even the walls are covered. You can only see it if you get really close, except for the few spots that the cleaner doesn't get, those spots are very noticeable. I had actually been considering getting a stainless steel brush a few months ago because of some algae that we had, but decided against it. Should I get a stainless steel brush and use it on the plaster, or is there some other way to remove it? Our plaster used to be so smooth, but now it is like sandpaper.
Gritty plaster
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the metal brushes are fine if your plaster is over a year old ... might consider a combo brush to be a little less harsh.
Was the pool smooth before the vacation, so it happened quickly ? Or could this have occurred more slowly?
Sounds like calcium scaling due to the high pH and maybe some interaction with dust/ sand in the water ... Although I am not sure.
Certainly get the pH back in the low 7s.
Do you have a full set of test results for us?
Posted from my Droid with Tapatalk ... sorry if my response is short
Was the pool smooth before the vacation, so it happened quickly ? Or could this have occurred more slowly?
Sounds like calcium scaling due to the high pH and maybe some interaction with dust/ sand in the water ... Although I am not sure.
Certainly get the pH back in the low 7s.
Do you have a full set of test results for us?
Posted from my Droid with Tapatalk ... sorry if my response is short
Sorry, the only thing I tested since we have been back was the chlorine and pH. The plaster was smooth just before the vacation. If you look close you can see the particles of sand actually stuck to the plaster. Certainly it could be scaling with sand stuck to it, but I wouldn't think scale would grow in just a few days. I always add a little extra acid before leaving town because it does naturally raise. The pH was 8.2 but I also wouldn't think that would be high enough for scale to form so quickly because it surely was 8.2 the entire week we were gone, but maybe only the last day or two.
A full set of test results would help a lot. Vegas tends to have hard water and a lot of evaporation, which can put the CSI very high very fast. You probably had some mild scaling already, and it tends to grow where it already has a hold. Plug your numbers into the pool calculator, including water temperature, and see what you have. Also, don't forget that anything above 8.2 pH will show as 8.2. You could have been much higher.
Las Vegas is known for sand storms. That sand is the type that can easily stick to plaster, especially new plaster. High pH, CH, and TA can also contribute to the sand sticking. IMO, once a plaster job is at least 2 or 3 months old, it is okay to use a stainless steel brush to remove the sand. If you don't remove the sand soon, it will just become more difficult to remove. In addition to brushing, lower the pH and TA to make the water slightly a negative CSI. Use the Pool Calculator to determine the amount of acid needed to adjust the pH down to 7.2 and a TA of about 50-60 ppm. But only keep the water like that temporarily while you brush for a few days. You can also read about the method on how to lower TA (if it is high).
I had that scaling on my intex pool last year and boy was it hard to get off. I bought a couple of heavy duty scrub brushes (prob just vinyl/plastic) and worked on it a little each day. I also used a spray bottle of vinegar water on the exposed areas but it was mostly a lot of elbow grease.