Formula Example

GPM * 0.012 * PPM = PPD
This formula calculates a required size chlorinator in pounds of chlorine per day (PPD), given the Gallons Per Minute (GPM) solution flow and the Parts Per Million (PPM) chlorine dosage.

For example, to calculate the PPD of chlorine feed required to treat 1,000,000 gallons-per-day (or 694.4 GPM) to a final concentration of
1 PPM:
694.4 * 0.012 * 1 = 8.33 PPD

In this case a 10 PPD Hydro Instruments Model 500 would be the minimum sized chlorinator to be used for this water treatment application.