Total Pool Solutions / Blog / Liquid chlorine dosing
How much liquid chlorine to add to a pool
Published October 11, 2026 by Total Pool Solutions, Miami
Short answer: in 10,000 gallons, about 10 fl oz of 12.5% liquid chlorine (or 13 fl oz of 10%) raises free chlorine by 1 ppm. Multiply by the ppm you need and by your pool size.
The formula
Fluid ounces = ppm to raise × gallons ÷ 10,000 × 10.2 (for 12.5%) or × 12.8 (for 10%).
Example: a 15,000-gallon pool at 1 ppm that you want at 4 ppm needs 3 ppm × 1.5 × 10.2 ≈ 46 fl oz of 12.5% liquid chlorine.
Chart by pool size
| Gallons | +1 ppm 12.5% | +1 ppm 10% | +3 ppm 12.5% | +3 ppm 10% |
|---|---|---|---|---|
| 10,000 | 10 fl oz | 13 fl oz | 31 fl oz | 38 fl oz |
| 15,000 | 15 fl oz | 19 fl oz | 46 fl oz | 58 fl oz |
| 20,000 | 20 fl oz | 26 fl oz | 61 fl oz | 77 fl oz |
| 25,000 | 26 fl oz | 32 fl oz | 77 fl oz | 96 fl oz |
| 30,000 | 31 fl oz | 38 fl oz | 92 fl oz | 115 fl oz |
Values are rounded. Liquid chlorine loses strength as it ages and in the heat, so an old jug may need more.
How to add it
- Run the pump and pour slowly in front of a return jet.
- Add chlorine by itself. Never mix it with acid or other chemicals.
- Retest after the water has circulated for about 30 minutes.
Why stabilizer (CYA) matters
Stabilizer protects chlorine from the sun, but it also makes chlorine work more slowly. A common rule of thumb is to keep free chlorine at about 7.5% of your CYA level. With 40 ppm of stabilizer, that is about 3 ppm of free chlorine.
Do the math for your pool
Our free pool chemical calculator does this for you, and also tells you how much acid, baking soda or stabilizer to add.