🧴 Liquid Chlorine (12.5%)
liquid sodium hypochlorite, 12.5% available chlorine · updated August 2026
Quick answer: add 10.7 fl oz per 10,000 gallons to raise Free Chlorine 1 ppm. Ideal Free Chlorine: 1–3 ppm (shock: 10–12 ppm). Add ½–⅔ first, circulate, retest.
Safety — read first
- • Never mix with any other chemical, especially acid — the reaction releases toxic chlorine gas.
- • Pour slowly around the pool's perimeter with the pump running.
The workhorse of pool sanitizing: fast-acting, adds no stabilizer and no calcium. Ideal for regular chlorination and shocking pools that already have enough CYA.
Side effects: Slightly raises pH. Loses strength in storage — buy fresh, store cool and dark.
Dosing chart
| Pool size | +1 ppm | +2 ppm | +5 ppm | +10 ppm |
|---|---|---|---|---|
| 5,000 gal | 5.3 fl oz | 10.7 fl oz | 26.8 fl oz | 1.7 qt |
| 10,000 gal | 10.7 fl oz | 21.4 fl oz | 1.7 qt | 3.3 qt |
| 15,000 gal | 16.0 fl oz | 1.0 qt | 2.5 qt | 1.25 gal |
| 20,000 gal | 21.4 fl oz | 1.3 qt | 3.3 qt | 1.67 gal |
| 30,000 gal | 1.0 qt | 2.0 qt | 1.25 gal | 2.51 gal |
Calculate your exact dose
1 · Your pool's volume
Working with 20,000 gallons
2 · What are you fixing?
Ideal Free Chlorine: 1–3 ppm (shock: 10–12 ppm). Adjusting pH? Doses aren't linear — see soda ash / muriatic acid.
3 · Add one of these
Slightly raises pH. Loses strength in storage — buy fresh, store cool and dark.
Adds ~0.7 ppm calcium hardness per 1 ppm FC — avoid if your CH is already high. Slightly raises pH.
Adds ~0.9 ppm CYA per 1 ppm FC — CYA builds up fast. Fine early season, switch to liquid or cal-hypo once CYA hits 30–50.
Adds ~0.6 ppm CYA per 1 ppm FC and is strongly acidic — expect pH and alkalinity to drift down with steady tab use.
Estimates from standard label dosing, to raise Free Chlorine by 2.5 ppm in 20,000 gallons. Add ½–⅔ of the dose first, circulate 4–6 hours, retest, then top up. Never mix chemicals with each other.
FAQ
How much liquid chlorine do I add per 10,000 gallons?+
10.7 fl oz per 10,000 gallons will raise Free Chlorine 1 ppm. Scale linearly with your pool size — the chart on this page covers 5,000 to 30,000 gallons.
What does liquid chlorine do to a pool?+
The workhorse of pool sanitizing: fast-acting, adds no stabilizer and no calcium. Ideal for regular chlorination and shocking pools that already have enough CYA. Side effect to know: Slightly raises pH. Loses strength in storage — buy fresh, store cool and dark.
Is liquid chlorine safe to handle?+
Never mix with any other chemical, especially acid — the reaction releases toxic chlorine gas. Pour slowly around the pool's perimeter with the pump running.