Gray mottling problem: PB Visit
Ok, the PB came to take a look... and oh, where do I begin. Nice fellow, and he said it could be 1) bad water chemistry, 2) hardness of the water, 3) workmanship. This is gonna be long, and if you don't feel like reading, just skip to the summary at the end.
I told him about how I've been doing my water chemistry, keeping CH between 200-400, mostly at 300 or below... and most importantly CSI as close to 0 as possible. He said I've been doing a very good job with the water chemistry, but still maintained that the water is VERY hard in the greater Houston area. He named some towns and neighborhoods that have the same problems, and it all depends on the city water, the source, and how hard they allow it to be. He said that one town could have very hard water with plaster problems, and the next town 5 miles away would have no problems. Since he kept saying the water here is "really really bad", I checked a water hardness map:
http://www.h2odistributors.com/water-hardness.asp
Turns out our water here is "moderately hard", or maybe I'm on the line between "moderately hard" and "hard", at least according to this map. Can water really vary that much from town to town, like the PB was saying? Btw, I tested my fill water a month ago and CH was 200. I'll retest that today just to be sure. I know that places like Arizona and Utah have water that is even harder, and surely they don't have plaster problems in every pool there??
They offered to acid wash the bottom half of the spa as a test. So they drained the spa, and acid washed it. Only the organic spotty stains came right off (dissolved would be the better word), but the gray mottling remained. It looks EXACTLY the same before and after the acid. The subs still said that they could acid wash the entire pool and there would be less stains. I was totally unconvinced, and peppered the PB with more questions about acid washing, life of the plaster, etc. He said even if they did an acid wash, the stains could come back later because the water is so hard. So I asked, "if the stains are going to come back, then what's the point in doing an acid wash?" He agreed, and said if it were him, he'd save his money and in 5 years, upgrade the plaster to something that would not allow the mottling to appear.
Then I asked them how much calcium chloride they put in the plaster, and they said they did NOT put any. They were adamant about it, and said it should be 0%. Then he asked me when the plaster was installed (March), and he said it could be 1% because they put a little in when the weather is a little cold. I told him that I'll get a plaster sample tested at a lab to verify his claim. I thought that would make him nervous, but on the contrary, he happily encouraged me to do so, and ordered one of his guys to get a sample off the drain area. They did, and I bagged the sample. PB told me to let him know once I got the results.
SUMMARY:
1. As a test, PB drained spa and acid washed bottom half. Organic spots came off, gray mottling looks exactly the same.
2. PB went on and on about how hard the water is in Texas, and lots of pools have the same problem.
3. PB and I agreed there's no point in an acid wash, told his subs to get me a plaster sample, and I'll send it to a lab to verify their claim of no calcium chloride in plaster.
4. PB said there's nothing more I can do, except upgrade to a "better" plaster.
All in all, it was a civil conversation and he was a very nice guy, but it feels like there's nothing I can do, except hope the test comes out more than 1%... if it did, then the PB would "take care of it".