 Disinfect Your Budget 1-pound of gas chlorine = 1 part per million (ppm) in a 120,000 gallon pool. *Average cost \$ .28 lb 1-gallon sodium hypochlorite (bleach) = 1 part per million (ppm) in a 120,000 gallon pool. *Average cost \$ .75 per gallon. 1 1/2 pounds calcium hypochlorite (tablets) = 1 part per million (ppm) in a 120,000 gallon pool. *Average cost \$1.60 per lb. The City of X used sodium hypochlorite (bleach) to disinfect their 3 swimming pools last year. The total number of gallons used for the year was 10,000. The cost of the bleach was \$0.75 per gallon, so the cost to disinfect City X's pools last year was 10,000 gallons X \$0.75 which = \$7,500.00 This year City X is thinking of changing to calcium hypochlorite (tablets) for disinfection. To do this it will take 1 1/2 lbs of calcium hypochlorite (tablets) per gallon of bleach it took last year. That is 1 1/2 lbs x 10,000 gals which equals 15,000 lbs The price of the calcium hypochlorite (tablets) was \$80.00 per 50 lbs bucket, which equals \$1.60 per lb. So \$1.60 x 15,000 lbs = \$24,000.00 That means the cost increase to change from bleach to tablets would be \$24,000.00 minus the \$7,500.00 it took last year which = \$16,500.00 That is \$16,500.00 plus the cost of the new feeders! The sales guy said it had something to do with chemistry? Seems reasonable right? 