Quote Originally Posted by waterbear
Math neve was my strong piont. Niether is typoing I dropped a 0! (and I treat 12.5% chlorine as 10% because it probably is by the time it goes in the pool! I was rounding off for simplicity. 100 oz is closer to 3 1/4 qts. (10 oz of 10% will raise 1000 gal 10 ppm) Thanks for catching that, Carl!

My point still holds. These pools are needing HUGH amounts of chlorine to reach breakpoint. 12 to 16 gallons in a 10000 gal pool means 120 or higher ppm chlorine!
LOL!

Remember my rule of thumb: 1 gallon will add EXACTLY it's concentration to 10,000 gallons. So 1 gal of 5.25% adds 5.25ppm FC, 1 gal of 12.5% adds-----10ppm! (when it should add 12.5ppm--and will if it's new and properly stored).

Yes, your point still holds. But a ppm of 120 is bad, real bad...I sure hope it isn't a vinyl pool. If CYA is that high, then water replacement is the best option.