Pool Chemical Dosing Calculator Formula

Understand the math behind the pool chemical dosing calculator. Each variable explained with a worked example.

Use the Pool Chemical Dosing Calculator

Formulas Used

Liquid Chlorine (12.5%)

liquid_chlorine_oz = pool_gallons * ppm_increase * 0.0013 * 128

Granular Chlorine (65%)

granular_oz = pool_gallons * ppm_increase * 0.00024 * 16

PPM Increase Needed

ppm_change = ppm_increase

Variables

VariableDescriptionDefault
pool_gallonsPool Volume(gallons)15000
current_ppmCurrent Chlorine Level(ppm)1
target_ppmTarget Chlorine Level(ppm)3
ppm_increaseDerived value= target_ppm - current_ppmcalculated

How It Works

Pool Chlorine Dosing

Maintaining proper chlorine levels (1-3 ppm for residential pools) requires calculating the right dose based on pool volume and current levels.

Simplified Dosing

Liquid Chlorine (12.5% sodium hypochlorite): ~1.3 mL per gallon per 1 ppm increase

Granular Chlorine (65% calcium hypochlorite): ~0.24 grams per gallon per 1 ppm increase

Always add chemicals to water, never water to chemicals. Add in the evening when UV degradation is minimal.

Worked Example

A 15,000-gallon pool needs chlorine raised from 1 to 3 ppm.

pool_gallons = 15000current_ppm = 1target_ppm = 3
  1. 01PPM increase = 3 - 1 = 2 ppm
  2. 02Liquid chlorine = 15,000 x 2 x 0.0013 x 128 = 4,992 fl oz = ~39 fl oz
  3. 03Granular chlorine = 15,000 x 2 x 0.00024 x 16 = 115.2 oz = ~7.2 oz

Ready to run the numbers?

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