How much liquid chlorine to add to a pool
Per 10,000 gallons, about 10 fl oz of 12.5% liquid chlorine (or 21 fl oz of 6% bleach) raises free chlorine by 1 ppm. How many ppm you need depends on your stabilizer, so enter your numbers for the exact pour.
Pour this much (+2 ppm)
Evening, pump running, in front of a return jet. Retest after 30 minutes. Need a shock instead? Shock calculator.
Chemical safety: read the product label first and follow it where it differs from this page. Add acid to water, never water to acid. Never mix chlorine products with acid or with each other, not even in a bucket. Add one chemical at a time with the pump running, wait at least 30 minutes (acid and chlorine: until the next test), and retest before topping up.
Liquid chlorine per 10,000 gallons
| Raise FC by | Liquid 12.5% | Liquid 10% | Bleach 8.25% | Bleach 6% |
|---|---|---|---|---|
| 1 ppm | 10.2 fl oz | 12.8 fl oz | 14.5 fl oz | 20.7 fl oz |
| 2 ppm | 20.5 fl oz | 25.6 fl oz | 29.1 fl oz | 1.3 qt (41 fl oz) |
| 3 ppm | 30.7 fl oz | 1.2 qt (38 fl oz) | 1.36 qt (44 fl oz) | 1.94 qt (62 fl oz) |
| 5 ppm | 1.6 qt (51 fl oz) | 2 qt (64 fl oz) | 2.27 qt (73 fl oz) | 3.24 qt (104 fl oz) |
| 10 ppm | 3.2 qt (102 fl oz) | 1 gal | 1.14 gal | 1.62 gal |
Scale linearly: 20,000 gallons needs double. Liquid strength is labelled as trade percent (pool chlorine) or weight percent (bleach); the table converts both to available chlorine.
What one jug does
| Jug | ppm in 10,000 gal |
|---|---|
| 1 gal liquid chlorine 12.5% | 12.5 |
| 1 gal liquid chlorine 10% | 10 |
| 121 oz bleach 8.25% | 8.3 |
| 121 oz bleach 6% | 5.8 |
How much free chlorine to aim for
CDC’s floor for home pools is 1 ppm, or 2 ppm if you use stabilizer. With stabilizer, a practical minimum is about 7.5% of CYA. See the full FC/CYA chart on the chlorine calculator, or work out your gallons on the pool gallons chart.
Questions pool owners ask
How much liquid chlorine do I add to my pool?
Gallons of pool × ppm increase ÷ 10,000 × the per-ppm amount for your strength. Per 10,000 gallons, +1 ppm free chlorine takes about 10.2 fl oz of 12.5% liquid chlorine, 12.8 fl oz of 10%, 14.5 fl oz of 8.25% bleach, or 20.7 fl oz of 6% bleach. How many ppm you need depends on your stabilizer: aim for about 7.5–11.5% of your CYA.
How much bleach do I add to my pool?
For 6% household bleach, about 21 fl oz per 10,000 gallons raises free chlorine 1 ppm; for 8.25% “concentrated” bleach about 14.5 fl oz. A full 121 oz jug of 8.25% bleach adds about 8.3 ppm to 10,000 gallons. Use plain, unscented bleach only.
How much bleach to shock a pool?
Shock level is roughly 40% of your stabilizer (and at least 10 ppm). At 40 ppm CYA that is 16 ppm, which for 15,000 gallons from 2 ppm means about 2.4 gallons of 8.25% bleach. Use the shock calculator for your exact numbers.
Does liquid chlorine lose strength?
Yes. Sodium hypochlorite breaks down over time, faster in heat and sunlight; a jug stored hot for a few weeks can be noticeably weaker than its label. Buy fresh, store cool and shaded, and test after dosing rather than trusting the label alone.
Is liquid chlorine the same as bleach?
Both are sodium hypochlorite in water. Pool liquid chlorine is usually 10–12.5% strength; household bleach is 6–8.25% and some versions contain fragrance or thickeners. Plain bleach works in a pool; you just need more of it.
When should I add liquid chlorine?
In the evening, with the pump running, poured slowly in front of a return jet. Sunlight destroys chlorine during the day, so evening dosing lasts longer. Never mix it with acid or other chemicals; add acid separately, at least 30 minutes apart.