Perhaps the PT rep doesn't know (what he should know) that adding calcium chloride to any color pigment cement product is considered detrimental to color uniformity, and can cause color fading and a blotchy mess. Companies that sell color pigments have written instructions that advises against adding ANY calcium chloride (not just a limit of 2%) to a colored (pigment) pool plaster (cement) mix. They instruct their end-users (plaster applicators) that calcium chloride is not compatible with color pigments, so there really isn't a very good excuse for not knowing that. But blaming water chemistry is easiest and seems to be the only consideration.
That fact is that quality plaster products are fairly forgiving, and the possibility that this plaster finish wasn't properly done with good material and good workmanship practices should be considered and addressed.
I also agree that lowering the pH to 7.2 only makes the water more aggressive and detrimental to a plaster finish as it will probably etch the cement portion of the pebble finish over time.
The Jack Magic guy may understand how to remove stains with chemical treatments, but that isn't going to solve and remedy this ongoing problem, because if anything, it will probably only be a temporary solution.
The best solution is to not add calcium chloride to color cement finishes in the first place.
That fact is that quality plaster products are fairly forgiving, and the possibility that this plaster finish wasn't properly done with good material and good workmanship practices should be considered and addressed.
I also agree that lowering the pH to 7.2 only makes the water more aggressive and detrimental to a plaster finish as it will probably etch the cement portion of the pebble finish over time.
The Jack Magic guy may understand how to remove stains with chemical treatments, but that isn't going to solve and remedy this ongoing problem, because if anything, it will probably only be a temporary solution.
The best solution is to not add calcium chloride to color cement finishes in the first place.