(Use with “Dosages Required” Chart & the “Breakpoint Superchlorination” Worksheet)
FAC = free chlorine; TAC = total chlorine; CAC = combined chlorine
1. How much Calcium Hypochlorite 67% will it take to reach breakpoint for a 120,000 gallon pool, if the FAC is 1.0 and the TAC is 1.5?
2. How much Chlorine Gas will it take to reach breakpoint for a 40,000 gallon pool, if the FAC is 1.0 and the TAC is 3.0?
3. How much Lithium Hypochlorite will it take to reach breakpoint for a 75,000 gallon pool, if the FAC is 0.6 and the TAC is 1.5?
EXAMPLE
How much Sodium Hypochlorite will it take to reach breakpoint for a 95,000 gallon pool, if the FAC is 1.0 and the TAC is 2.0?
STEP 1: Adjustment. For the adjustment, we take (TAC – FAC = CAC) x10=BP-FAC. We subtract the TAC-FAC to get the CAC and multiply the CAC by 10. That is our breakpoint number, then we need to subtract the FAC from that number. That’s our adjustment. (In our example, TAC – FAC (2.0 -1.0) is a CAC of 1.0. We multiply 1.0 x 10 =BP 10 – FAC 1.0 = 9.0)
STEP 2: Amount of Chemical. The amount of chemical is taken from the “Dosages Required” Chart for the chlorine you are using. In our example, we are using sodium hypochlorite. Therefore, our amount is 10.7 Fluid Ounces.
STEP 3: ppm in Bold. The ppm in Bold is taken from the “Dosages Required” Chart just above the chemical you are using. In all these cases, the ppm in Bold is 1 ppm.
STEP 4: Volume. Volume is usually given for these problems. Or see Volume problems to learn how to figure out pool’s volume. Our volume is 95,000 gallons.
STEP 5: We divide our answer for Step 1 by our answer for Step 3. 9 ÷ 1 = 9.
STEP 6: We divide our answer for Step 4 by 10,000. 95,000 ÷ 10,000 = 9.5.
STEP 7: We multiply Step 2 by Step 5 by Step 6. 10.7 fl. oz. x 9 x 9.5 = 914.85 fl. oz.
ANSWER: It takes 914.85 fl. oz. of sodium hypochlorite to reach breakpoint.
(914.85 fl. oz. ÷ 128 fl. oz. Per gallon = 7.18 gallons)
ANSWERS
1. 96 Oz. Of Calcium Hypochlorite 67% (96 oz. ÷ 16 oz. Per lb. = 6 Lbs.)
2. 98.8 oz. Of Chlorine Gas (98.8 oz. ÷ 16 oz. Per lb. = 6.175 Lbs.)
3. 239.4 Oz. Of Lithium Hypochlorite (239.4 oz. ÷ 16 oz. Per lb. = 14.96 Lbs.)
