Ben and Waterbear,

Thanks for your replies. I'll keep a close eye on things this year, and make sure I don't have too much total Alk if I use the Soda Ash.

I'm in recovery from copper overload from last season, having managed to keep my pH low enough (via the use of two floaters with tri-chlor pucks) to corrode my heater core. No wonder my pH wouldn't budge--it was the tri-chlor.

Anyway, I got the cover off yesterday, and the pool still looks green (not algae, mineral).

I've got the submersible pump running, and I'm going to dilute out again, then I think I will try an additional ascorbic acid treatment to get the liner to release the copper that is staining it.

If that looks ok, I'll do another dilution, and then just try to precipitate it out and keep rinsing off my filter cartridges. Then, hopefully, I can get my pH back in line, and then I'll stick with bleach for my chlorination.

The weather in Minnesota is beautiful today.

Boris