I had a company re plaster my pool in Arizona, (white plaster) 2 years ago in the spring. Within 6 months, or when the water temperature cooled off, the bowl of the pool turned black, I also had other smaller black/rust stains appear at that time. It was like overnight or within a couple of days this took place. I have pool service weekly and have had the same company for years. The company that re plastered the pool, came back out, and tried to treat the "stains" with chemicals, but the stains were still there. They finally drained the pool, chipped out the black spots and re plastered them. They said once the plaster cured it would blend in, NOT! I called them back out and they sanded down the areas that they had repaired, and the area around the repair turned black. I had the owner out a few days ago and he now is telling me we have to drain the pool yet again and he is going to attempt to sand down the entire plaster surface of the pool. I had the pool resurfaced to make it look new, and now all it looks like is a giant repair job, and I am getting ready to sell this property. I am FURIOUS! I need to know what my best course of action is at this point. I do not believe that sanding the entire surface is going to make the repair spots blend in any better. What should they be doing to this pool at this point? The owner basically admitted to me that there was a problem with the product they used, but that's not my fault! At this point I am ready to sue this company if they don't do an entire re plaster of this pool…..HELP!