How much liquid chlorine to raise 1 ppm in 10,000 gallons?
About 10.2 fl oz (1.3 cups) of 12.5% liquid chlorine raises free chlorine by 1 ppm in 10,000 gallons. With 10% chlorine it takes about 12.8 fluid ounces.
How to work it out
- In short: work out how much chlorine the rise takes, then how much of your jug holds that much — the label % says how strong it is.
- 1 ppm × 37,854 L (10,000 gal) = 37.9 g of chlorine
- 12.5% = 125 g of chlorine per litre → 0.303 L = 10.2 fl oz (1.3 cups)
- 10.2 fl oz (1.3 cups) ÷ 1 gal per container = 0.08 → 1 container
This is the number worth memorising, because every other liquid chlorine dose is a multiple of it. Ten fluid ounces is a little over a cup and a quarter — so “a cup and a quarter per ppm per 10,000 gallons” is a handy rule for 12.5% chlorine.
Adjust for your project
More options: Jug
- Containers
- 1 container · 1 gal jug
- Per 1 ppm
- 10.2 fl oz (1.3 cups)
- Salt it leaves behind
- 1.6 ppm
- Liquid chlorine and bleach lose strength in storage, faster when warm. A jug that has sat through a summer may raise chlorine noticeably less than this — test after 30 minutes of circulation.
1 ppm rise in 10,000 gallons, by strength
| Strength | Pour in |
|---|---|
| 5.25% | 24.4 fl oz (3 cups) |
| 6% | 21.3 fl oz (2.7 cups) |
| 7.5% | 17.1 fl oz (2.1 cups) |
| 8.25% | 15.5 fl oz (1.9 cups) |
| 10% | 12.8 fl oz (1.6 cups) |
| 12.5% | 10.2 fl oz (1.3 cups) |
Scaling the 1 ppm rule
Multiply by the ppm you want and by your pool size in ten-thousands of gallons:
- 3 ppm in 10,000 gallons: 3 × 10.2 ≈ 31 fl oz (just under a quart).
- 2 ppm in 25,000 gallons: 2 × 2.5 × 10.2 ≈ 51 fl oz.
- 1 ppm in 5,000 gallons: half, about 5 fl oz.
- 10 ppm (shock) in 10,000 gallons: about 102 fl oz, a little over three quarts — see how much liquid chlorine to shock a 10,000 gallon pool.
Why the rule works: 1 ppm is 1 mg per litre, and 10,000 gallons is 37,854 litres, so 1 ppm is 37.9 g of chlorine. At 12.5% (125 g per litre) that is 0.30 litres, or 10.2 fl oz. The same arithmetic at 10% strength gives 12.8 fl oz, and at 6% bleach about 21 fl oz.
Two things make the real rise differ from the rule. Chlorine sold as 12.5% sodium hypochlorite by weight is a bit stronger than 12.5% read as grams per 100 ml, and every jug weakens as it ages — so measure once: add a known dose in the evening, wait half an hour, and see how far it moved. If 10 fl oz gives you 0.8 ppm, your jug is about 10 percent available chlorine by that standard and you can scale every future dose. For the bleach version of this rule, see how much bleach for a 10,000 gallon pool.
Different size? Use the full Liquid Chlorine & Bleach Calculator.
What you’ll need
- Measuring pitcher (marked in oz and ml)Budget price
Measure doses instead of glugging from the jug. Keep one for acid and a separate one for chlorine.
See options on Amazon (opens in a new tab) - Liquid pool chlorine (sodium hypochlorite)Budget price
Adds chlorine without stabilizer or calcium. Strength is printed on the label — commonly 10% or 12.5% — and it weakens with age and heat, so buy it fresh.
See options on Amazon (opens in a new tab) - FAS-DPD drop test kit (chlorine, pH, TA, CH, CYA)Mid-range price
A drop-count kit reads free chlorine to 0.5 ppm (or 0.2 ppm), plus pH, alkalinity, calcium and stabilizer. Every dose on this site starts from a test, so this is the one thing worth buying first.
See options on Amazon (opens in a new tab)
As an Amazon Associate we earn from qualifying purchases. Links to products are affiliate links — they cost you nothing extra and help keep these calculators free.
Frequently asked questions
How much 10% liquid chlorine raises 10,000 gallons by 1 ppm?
About 12.8 fl oz (1.6 cups).
How much liquid chlorine raises a 20,000 gallon pool by 1 ppm?
About 20.5 fl oz (2.6 cups) of 12.5% liquid chlorine.
How much 6% bleach raises 10,000 gallons by 1 ppm?
About 21.3 fl oz (2.7 cups) of plain 6% bleach.
Other common sizes
- How much bleach for a 10,000 gallon pool — 64 fl oz (2 qt)
Sources
- OxyChem — Soda Bleach Solutions Handbook (re-hosted copy) (opens in a new tab) — Trade percent = grams per litre of available chlorine ÷ 10; weight % NaOCl ≈ 1.05 × weight % available chlorine; strength and specific gravity table.
- HASA — Hasachlor sodium hypochlorite SDS (2026) (opens in a new tab) — Pool liquid chlorine: sodium hypochlorite 12.5% by weight, about 1.2 g/ml.
- Hill Brothers — Sodium hypochlorite 12.5% specifications (opens in a new tab) — 12.5% by weight = 142 g/L available chlorine (14.2 trade percent), 11.9% available chlorine by weight.
- Pool Essentials chlorinating liquid (retail listing) (opens in a new tab) — A 10% sodium hypochlorite pool chlorine.
- CloroxPro — Germicidal Bleach (retail listing) (opens in a new tab) — A concentrated household-type bleach at 8.25%.
- Clorox Regular Bleach SDS (2020) (opens in a new tab) — Household bleach: sodium hypochlorite 5–10% by weight.
- CDC Healthy Swimming — Home pool and hot tub water treatment and testing (opens in a new tab) — pH 7.0–7.8; free chlorine at least 1 ppm in pools (2 ppm with cyanuric acid) and 3 ppm in hot tubs; no CYA in hot tubs; test twice a day.
- CDC Healthy Swimming — Inflatable and plastic kiddie pools (opens in a new tab) — Empty kiddie pools at least daily; it is unsafe to add chlorine or bromine to them.
- CDC — Pool chemical injuries press release (2014) (opens in a new tab) — Never mix pool chemicals, especially chlorine products with acid; add chemical to water, never water to chemical.
- CDC — Pool chemical safety: storage poster (opens in a new tab) — Separate acid and chlorine; don’t mix different types of chlorine; keep chemicals cool, dry and in original containers.