I tested the water after running the pump for a few hours and my CH is at 360. The water from the tap is about 210 so I don't think I'll be able to bring it down much more.

Keep the alk a little low and the pH no more than 7.5 and that should keep the CSI near neutral to slightly negative. This will prevent scale formation. The rough spots, if the marcite is too thin can be lightly sanded with extra fine to fine wet/dry sand paper, assuming there aren't too many.

I assume you were using 3" tabs to chlorinate?

Scott

Yes I was using 3" pucks and powdered shock. I assume the shock is what brought the ch level back up. I'm thinking about draining half of the pool again this weekend. I have flagstone coping and have heard bad thing about swg with flagstone. I guess I'll try bleach. The rough spots are small and mainly on the edge of the seats. Is the white powder plaster? Will i have anymore damage if I keep my balance right?

just wear.Marcite plaster lasts 8 to 12 years.

Flagstone is a generic term. Some varieties are softer than others, The softer ones benefit from being sealed periodically.

Stick with 6% unscented bleach like Clorox for chlorine boosts. One big jug provides about the same amount of chlorine a 1 lb pouch of cal-hypo 68%, Actually its a little less but close enough.

Scott

Thanks for the help. I'll try to chlorox for a while and see how much trouble it is. The coping is OK flagstone. I've read that might be a little harder and can handle salt. I might try it with the bleach is a lot work.

OK Flag flakes pretty readily with or without salt. Seal it. It'll last longer.

Get a proper test kit. One which can test chlorine to 50 ppm, CH, TA, pH, and CYA. While 50 seems like a high number, if you're at 30 ppm CYA, shocking level might be 30 or 40 for chlorine.

Scott