Pool RatioFree chlorine by stabilizer (CYA)
| CYA (ppm) | Minimum FC | Target FC | Shock FC |
|---|---|---|---|
| 0 | 1 | 2 | 10 |
| 20 | 1.5 | 2.3 | 10 |
| 30 | 2.3 | 3.5 | 12 |
| 40 | 3 | 4.6 | 16 |
| 50 | 3.8 | 5.8 | 20 |
| 60 | 4.5 | 6.9 | 24 |
| 70 | 5.3 | 8.1 | 28 |
| 80 | 6 | 9.2 | 32 |
With no stabilizer, sunlight burns chlorine off within hours, so outdoor pools usually keep CYA at 30–50 ppm (60–80 for salt pools). The higher the CYA, the more free chlorine you need to keep for the same sanitizing power.
Scaling to your pool
- Dose = chart amount × (your gallons ÷ 10,000) × ppm to raise
- 15,000 gal, +3 ppm, 10% liquid: 12.8 fl oz × 1.5 × 3
= 58 fl oz
Frequently asked questions
How much liquid chlorine per 10,000 gallons?
About 12.8 fl oz of 10% liquid chlorine raises free chlorine by 1 ppm in 10,000 gallons, or 10.2 fl oz of 12.5%.
How much bleach per 10,000 gallons?
About 21.3 fl oz of 6% unscented bleach per 1 ppm. Check the label: many “regular” bleaches are 7–8.25% now, so you need less.
What free chlorine should I keep for my stabilizer?
About 7.5% of CYA as a minimum and 11.5% as a target; shock level is about 40%. The second table lists them.