PPM --- How do I figure IT

[CarlD]

Figure 15,000 gallons for your calculations...if you have 4' of water the actual number is about 14,700 gallons + or - 14 gallons. But nothing's that accurate and 15,000 is MORE than good enough--makes rule-of-thumb and ballpark calculations easy.
1.5 gallons of 6% bleach adds 6ppm of chlorine to your water. 1 gallon only adds 4ppm. If you buy 12.5% liquid chlorine at a pool store it should add 8.5 ppm of chlorine per gallon.

Carl

[madwil]

just a note- when you are shocking that high, you're pH test is not accurate- higher chlorine (I think over 10) makes the pH read high.
If it's really high, adding acid should be alright, but don't shoot for the low end of pH while your chlorine is over 10...