Calculating the Required Chlorine (The Formula)

Introduction
A common question for pool operators is: “How much chlorine should I add to achieve a certain residual level?” The answer involves a straightforward calculation based on pool volume and the desired rise in chlorine.

The Formula

(Desired mg/L increase) × (Pool volume in liters) ÷ (Concentration of product) ÷ 1000

  • Desired mg/L increase: The difference between current and target chlorine levels. For example, from 1 mg/L to 3 mg/L is an increase of 2 mg/L.
  • Pool volume: For a 100 m³ pool, that’s 100,000 liters.
  • Product concentration: The percentage or g/L of the chlorine solution or powder.

Example

If you want to raise chlorine by 2 mg/L in a 100,000 L pool using a 10% chlorine solution:

(2 × 100,000) ÷ 10 ÷ 1000 = 20 liters of chlorine solution

Back to home