Quality Example: I noticed yesterday a different brand of thin set in the stack. I had checked the other brand technical documentation and found it's correct use. So I checked the different bag. Technical documents are readily available online. Turns out the product is a quality brand and usable outside/inside but specifically excluded for pools. So I showed the crew the documents and why it's prohibited. This morning the bags were still there so I required they remove it from site. No need to tempt fate. How did this happen? These guys work for many different pool builders that vary greatly in quality. I'm quite certain I've seen pools under construction with these same "NOT FOR POOLS" documentation. Many craft labor will say "I do this all the time for PB's". I'm sure it's true but not for the really good PB's and there are many, more not good PB's unfortunately. Also, it's much easier to get since it's available from big box stores. The approved brands may be also sometimes but I haven't found them in construction quantities any place other than pool product distributors.