We are new pool owners and new to this Forum. We have a 16,500 I/G gunite SWG pool. The Filter is a Jandy CL460 Cartridge Filter and we have a Aquapure Ozone Generator. The salt was added a little over a week ago. My current test results are;
FC – 4
TC – 4
ALK – 90
PH – 7.4
CYA – 30
PHO – 100
CAL - 150

We have dark grey plaster and have recently been noticing the plaster was lighter in color in numerous places, mainly in the deep end. We brought it to our Pool Builders attention and he had the Plaster people come out. They told us that it was from what they called White Scale. They told us to keep the PH at 7.2 and it should clear up in a week or so. I have been doing my best to keep the PH at 7.2 but it is all over the place. I have added almost 2 gallons of acid in the last week and have had a PH reading as high as 8.0. I have a Taylor K2005 test kit and have been testing the PH daily and everything else 2/3 times a week. Do I need to add CYA to keep the PH more stable? If so how much? Also what is White Scale? And is lowering the PH the way to correct it?