I have a new pool, built in Nov 2022. In the spring we noticed some white spots in the plaster (NPT plasterscapes deep blue harbor). As the year progressed the spotting went from white to a grey discoloration. The discoloration is most prevelant on the stairs, ledge and deep end seat. The plaster company came out and did an acid bath (4 times) on one section determined to prove it was calcium. It wasn't and they just ended up scratching the heck out of the plaster with sand paper. They then decided it must by cyanuric acid staining due to poor water chemistry and told us we're SOL. I can prove through regular third party water tests not just my weekly testing that our water has always been balanced and our CYA has never been high. They are still determined to blame CYA staining and water chemistry despite zero evidence to support that and an abundance to dispute it. This back and forth has been going on for a while and in the meantime I found other customers with similar complaints who are being told the same thing despite professional pool service and documentation stating otherwise. This seems to be a pattern. I believe the issue is actually white spotting. The only way they will honor the warranty is if I can prove it's white spotting with plaster testing. At this point I'm ready to move forward with testing, but I don't know where to start to find a company to do the testing. Can anyone here recommend a company or direct me to where I would find such a company? I'm in Northern CA if that helps. Thanks