Use muriatic acid to lower the pH, about 1/4 of a gallon poured into your pool per dose. (Pump on 24/7; wear gloves and glasses, don't breathe fumes; rinse bottle off in pool after recapping, rinse spill or splatters off promptly; purchase at hardware store)

As long as you've got both *some* chlorine and the polyquat, the pool is swimmable.

United Chemical Products tend to be unlike any other companies; most contain sodium bromide and/or ortho phosphates. Pool Stain Treat is, as I recall, oxalic acid and probably some phosphates. It's NOT the sort of thing I'm talking about.

Trichlor tabs are - I think - available almost everywhere in the country. Lowes, Home Depot, Walmart and Sams proabably all have them near you. They are 3" - 4" diameter round white tables used in skimmers, floaters or feeders and contain trichoro-isocyanuric acid, a form of chlorine and stabilizer combined together.

Ben