Pool Chlorine Dosage Calculator
Calculate exactly how much chlorine to add to your pool. Get precise dosages for liquid chlorine, dichlor, and cal-hypo based on your pool size and current readings.
Average residential pool: 10,000-20,000 gallons
Stabilized pools need higher chlorine levels (3-5 ppm vs 1-3 ppm)
Ideal Range: 3-5 ppm (with stabilizer)
Chlorine is too low - sanitization may be inadequate
To raise chlorine from 1 to 3 ppm:
Liquid Chlorine
Sodium Hypochlorite (12.5%)
30.0 oz
Granular Dichlor
Sodium Dichlor (56%)
6.0 oz
Cal-Hypo
Calcium Hypochlorite (65-73%)
6.0 oz
Safety: Never mix different chlorine types. Add chemicals with pump running. Wait 15-30 minutes between additions. Test after adding.
Understanding Pool Chlorine
Chlorine is the most common pool sanitizer, killing bacteria, algae, and other harmful organisms. Maintaining proper chlorine levels is essential for safe swimming and clear water.
Types of Pool Chlorine
Liquid Chlorine (Sodium Hypochlorite)
- • 10-12.5% available chlorine
- • Fast-acting, no residue
- • Does not add CYA (stabilizer)
- • Best for: Daily maintenance, shocking
Dichlor (Sodium Dichloro-s-Triazinetrione)
- • 56% available chlorine
- • Contains stabilizer (CYA)
- • Dissolves quickly, pH neutral
- • Best for: Initial treatment, hot tubs
Cal-Hypo (Calcium Hypochlorite)
- • 65-73% available chlorine
- • Adds calcium to water
- • Unstabilized (needs CYA separately)
- • Best for: Shocking, soft water pools
The Chlorine-CYA Relationship
Cyanuric acid (CYA) protects chlorine from UV degradation but also reduces its effectiveness. The key is maintaining the right ratio:
| CYA Level | Minimum FC | Target FC |
|---|---|---|
| 0 (no stabilizer) | 1 ppm | 2-3 ppm |
| 30 ppm | 2 ppm | 3-4 ppm |
| 50 ppm | 4 ppm | 4-6 ppm |
| 70+ ppm | 5 ppm | 6-8 ppm |
Frequently Asked Questions
How much chlorine should I add to my pool?
The amount of chlorine depends on your pool size, current chlorine level, and whether you use stabilizer (CYA). Generally, to raise chlorine by 1 ppm in a 10,000 gallon pool, add about 10 oz of liquid chlorine (12.5%) or 2 oz of granular chlorine.
What is the ideal chlorine level for a pool?
For pools with cyanuric acid (stabilizer), maintain 3-5 ppm of free chlorine. For pools without stabilizer, 1-3 ppm is sufficient. The key is the ratio of chlorine to CYA - chlorine should be about 7.5% of your CYA level.
What is the difference between liquid chlorine and granular chlorine?
Liquid chlorine (sodium hypochlorite) is fast-acting and doesn't add CYA, making it ideal for ongoing maintenance. Granular dichlor contains stabilizer (CYA) which protects chlorine from sunlight but can build up over time. Cal-hypo adds calcium to the water.
Can I add too much chlorine to my pool?
Yes, chlorine levels above 5 ppm can irritate skin and eyes. Very high levels (10+ ppm) can damage pool equipment and swimwear. If chlorine is too high, simply wait - sunlight and organic matter will reduce it naturally.
Should I add chlorine in the morning or evening?
Add chlorine in the evening or at night. Sunlight destroys chlorine rapidly - up to 90% can be lost in 2 hours of direct sun. Adding chlorine at dusk allows it to work overnight without UV degradation.
How often should I add chlorine to my pool?
Most residential pools need chlorine added every 1-3 days during swimming season. Test daily and add chlorine when levels drop below the minimum for your pool type (1 ppm without CYA, 3 ppm with CYA).
Learn More About Pool Chemistry
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