Second Go Around w/ Replaster and Concerned w/ Spots

[ConcernedTX]

My contractor finished a replaster for a 2nd time. 1st had stains where hose filled down the steps & other issues. The replaster was done on Sunday. I came home to pool after being out of town Monday night. I started the filtration that night & brushed twice starting the next day. To my knowledge nothing was added to the pool. When brushing I noticed a large spot of white that did not move like the plaster dust. I told the contractor. His guy came out today and put about 4 gallons of muriatic acid in pool. The plaster dust is now gone but these large spots are terrible. I'm concerned if these will come out or not. Pool is 15,000 gallons, chlorine pool.

Your help is greatly appreciated!

 

[JasonLion]

Welcome to TFP!

It would be helpful to see a complete set of water test results.

 

[ConcernedTX]

Got test at Leslie's yesterday around 5pm.
PH 8+
TA 90
CYA 20
CH 110
Phosphates 50
Nothing else was tested

 

[ConcernedTX]

Tests from today:
FAC 0
pH as low as can test <6.0
TA 0
CYA 20
CH 100
Phosphates 0

 

[ConcernedTX]

Should the pool pump be running when the ph is so low? Contractor has ph very low to get rid of spots.

 

[onBalance]

Pump should not be running with pH below 6.0.
Any way of determining if white areas are smooth to the touch and is the same as dark areas?