well the saga continues...
We noticed some color inconsistency about a month after the pool was filled.
I swam down and inspected it and noticed that the darker areas appeared to have less of the fine aggregate present exposing more of the pebbles in the finish.
I contacted the builder/Pebble Tec installer and they want to do a drain and acid wash tomorrow.
The only logical explanation is a poor acid wash the day after the Pebble Tec was initially installed??
Complete waste of 22,000 gallons of water - not to mention the time and money needed to fill and rebalance it.