thanks for the spreadsheet Biggs... on another note though... I believe that my calcium is a bit high.. last I checked it was at close to 500.. I didn't even check my alkalinity or mag... but I was wondering if you know of a way to drop the big 3 slowly... could I stop dosing two part for like a day or two? I will test all 3 tomorrow and see what I find... did a WC today..