We have done a lot of Hydrazzo over the years. The discoloration is not normal.

The CLI rep is correct. There was/is a chemical imbalance. Most failures on plaster are because of improper chemical treatment. Especially upon initial filling and start up.

Thank you for your feedback Mystic Pools. If you don’t mind my asking, in your experience, is this type of discoloration from chemical imbalance (startup or otherwise) only an aesthetic issue, or does it indicate a potential structural/longevity issue with the plaster? In either case, is there a solution short of re-plastering? The CLE rep said it could just be drained, re-polished, and then make sure chemistry is good moving forward. Or could just re-balancing the chemicals fix it without even re-polishing?

The chemical imbalance was the original issue. Trying to re-balance will have no effect.

Your best bet is to re-polish the spa. The prep and polishing process should clean up the surface to the original look without having to replaster.

The National Plasterers Council has on their site the recommended water chemistry guidelines. https://www.nationalplastererscouncil.com/water-chemistry/

It would also be worth reaching out to the CLI rep for their input on their preference for balancing with their product.