Risks with high alkalinity?

[Tredge]

For what it's worth, the pH stabilization at 7.8 is "predicted" by my spreadsheet and the CO2 graph except that on the graph I made it's off the chart (looks like I need to make a new graph for you high alkalinity folks ). As for your calcium hardness, you really don't want it to get to 0 if you have a plaster/grout pool. The problem with near 0 calcium isn't scaling, but corrosion (not of metal, but of plaster/grout). Is your pool vinyl? Is your CYA near 80 since you have an SWG? Mostly I'm asking just to get a sense of everyone's pool so I can see where the models start to break down.

Richard

I have a heavy epoxy coating on the pool so the grout and plaster are protected.

I have my CYA at 40. I'm reluctant to follow instructions and bump it to 80