The amount of chlorine to add to a pool depends on the pool size, current chlorine level, and the form of chlorine used (tablets, granules, or liquid). The goal is to maintain a chlorine level between 1 and 3 parts per million (ppm) for proper sanitation.
Recommended Chlorine Levels
- Outdoor pools: 0.5 to 3 ppm
- Indoor pools: 0.5 to 1.5 ppm
- Spas: 1 to 3 ppm
General Dosage Guidelines by Chlorine Type and Pool Size
Chlorine Type| Dosage per 5,000 gallons (approx.)| Notes
---|---|---
3-inch tablets| 1 tablet| Use 1-inch tablets for smaller pools to avoid over-
chlorination345
Granular chlorine| 2 to 3 ounces (4 to 6 tablespoons)| For 20,000 gallons,
about 7 ounces total48
Liquid chlorine| 0.5 gallon| For 20,000 gallons, about 2 gallons total; add in
evening, pre-diluted468
How to Calculate and Add Chlorine
- Test your pool water to determine the current chlorine level.
- Calculate how much chlorine is needed to raise the level to the target (1-3 ppm).
- Add chlorine according to the product instructions and pool volume.
- For liquid chlorine, add it in the evening or at night to reduce degradation by sunlight, pre-dilute in water, and pour slowly around the pool perimeter with the pump running
- Retest chlorine levels regularly (at least weekly) and adjust dosage as needed
Example for a 15,000-gallon pool
- Tablets: 3 to 4 three-inch tablets per week
- Granules: 5 to 9 ounces per week
- Liquid: 1.5 gallons per week
Additional Notes
- For shock chlorination, higher doses are used (e.g., 5-8 g granular chlorine per 1,000 liters)
- Always follow manufacturer instructions on packaging for precise dosing.
- Adjust dosage based on factors like sunlight, bather load, and water temperature, which affect chlorine demand
In summary, maintain chlorine at 1-3 ppm by adding the appropriate amount of tablets, granules, or liquid chlorine based on your pool size and current chlorine level, testing regularly to keep water safe and clean.
