A little more than one week after Eden colored re-plaster job, pool startup person employed by pool contractor came over in the morning and added what he said was 3 "scoops" of calcium chloride. He briefly brushed the bottom where the calcium was added and left. I was gone all that day but the next morning I found an undissolved mass of calcium chloride at the bottom of the pool. Brushed it away and plaster now has a dark stain surrounded by a white ring. Pump has been running 24/7 since startup, water had been balanced during the first week for TA (baking soda), and maintained for Cl (liquid) and pH (muriatic) and no chemistry changes were being made at the time the calcium was added.
The pool contractor has been notified and attempted to brush the area with a stainless steel brush with no effect. At this time he's trying to contact his plaster expert for advise.
Here's a photo of what I found and what it looked like after a quick brush. Does anyone have any recommendations for a fix?