Do *NOT* dump 25# of chlorine in there -- it will 'break' some, if not all of the HEDP, and could drop any metals out on your liner. Do *NOT* raise the pH (add borates) yet.

Have you used the polyquat? Can you get more? Can you get DE locally? Can you easily get calcium hypochlorite locally for a reasonable price (< $4/lb)?

(By the way, thanks for the comparison test results -- that's very helpful info for us. If you can, once you begin adding CYA, and do CYA testing, I'd love to see a comparison on those test results.)