How much sodium hypochlorite is required to raise the free chlorine in a 120,000-gallon pool to 5 ppm?

To determine the amount of sodium hypochlorite required to raise the free chlorine level in a 120,000-gallon pool to 5 parts per million (ppm), we need to understand how to calculate the chlorine dosage.

First, note that 1 million gallons of water contains 1 ppm of any substance in 8.34 pounds per million gallons. To raise the chlorine level by 5 ppm in a 120,000-gallon pool, you can use the following formula:

1. Calculate the total weight of chlorine needed:

• Since 1 ppm is equivalent to 8.34 pounds in 1 million gallons, we can set up that calculation:

• For 120,000 gallons, the weight of chlorine needed for 5 ppm would be:

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\text{Weight of chlorine} = 5 , \text{ppm} \times 120,000 , \text{gallons} \times \frac{8.34 , \text{pounds}}{1,000,000 , \text{gallons}} = 5 \times 120 , \text{pounds} = 4.17 , \text{