Chlorine Dosing Chart
A chlorine dosing chart showing how much 12.5% liquid chlorine and 73% cal-hypo it takes to raise free chlorine by 1, 3, and 5 ppm in 5,000, 10,000, and 20,000 gallon pools.
Quick answer: In a 10,000-gallon pool, 10.7 fl oz of 12.5% liquid chlorine or 1.8 oz of 73% cal-hypo raises free chlorine by 1 ppm. Halve those for 5,000 gallons, double them for 20,000 gallons, and multiply by the ppm you want to add. Always run the pump while dosing, add chemical to water, never mix chlorine types, and retest before adding more.
This chart shows how much chlorine it takes to raise your free chlorine by a set amount, for the two most common unstabilized products: 12.5 percent liquid chlorine and 73 percent cal-hypo. Both are ideal because neither adds cyanuric acid. Find your pool volume, decide how many ppm you need to add, and read the dose. For an exact figure tied to your real gallons, use the chlorine calculator.
Liquid chlorine (12.5%) dosing chart
Amounts are fluid ounces of 12.5 percent sodium hypochlorite. One cup is 8 fl oz, one quart is 32 fl oz, and one gallon is 128 fl oz.
| Pool volume | Raise FC by 1 ppm | Raise FC by 3 ppm | Raise FC by 5 ppm |
|---|---|---|---|
| 5,000 gal | 5.3 fl oz | 16 fl oz (2 cups) | 27 fl oz |
| 10,000 gal | 10.7 fl oz | 32 fl oz (1 quart) | 53 fl oz |
| 20,000 gal | 21.3 fl oz | 64 fl oz (half gallon) | 107 fl oz |
Cal-hypo (73%) dosing chart
Amounts are ounces by weight of 73 percent calcium hypochlorite. One pound is 16 ounces.
| Pool volume | Raise FC by 1 ppm | Raise FC by 3 ppm | Raise FC by 5 ppm |
|---|---|---|---|
| 5,000 gal | 0.9 oz | 2.7 oz | 4.6 oz |
| 10,000 gal | 1.8 oz | 5.5 oz | 9.2 oz |
| 20,000 gal | 3.7 oz | 11 oz | 18.3 oz |
These figures assume product at its labeled strength (12.5 percent liquid, 73 percent cal-hypo). Liquid chlorine weakens over time and in heat, so an older jug may need a bit more. If your product lists a different concentration, scale the amount accordingly.
Common unstabilized chlorine products
CPDI Champion Liquid Pool Shock, 12.5% Sodium Hypochlorite
Ready-to-use liquid chlorine for daily dosing and shocking.
In The Swim Pool Shock 68% Cal-Hypo Granular (12 x 1 lb)
$49.99 on Amazon
Concentrated granular chlorine; pre-measured one-pound bags.
Pool chemical safety (read before dosing)
Pool chlorine is powerful and demands care. Follow these rules every time:
- Never mix pool chemicals. Combining different chlorine types, or chlorine with acid, can release toxic gas or even cause a fire. Add one product at a time, and rinse any shared bucket or scoop between uses.
- Always add chemical to water, never water to chemical. When pre-dissolving cal-hypo, fill a bucket with pool water first, then add the granules slowly while stirring.
- Run the pump. Dose with the pump on so the chemical disperses quickly and evenly instead of pooling on the floor.
- Broadcast or pre-dissolve per the label. Pour liquid chlorine slowly around the deep end; broadcast or pre-dissolve cal-hypo to avoid bleaching liners or staining plaster.
- Retest before re-dosing. Wait 20 to 30 minutes, then test free chlorine before adding any more, so you never overshoot.
- Store safely. Keep chemicals in original containers, separated from one another, and away from kids, pets, heat, and sunlight.
These dosing figures are estimates from standard pool-care formulas. Your real result depends on your exact volume, product strength, and water chemistry, so always test your own water.
Dose to a target, not just a number
How much chlorine you need depends on your pool volume and how far your free chlorine sits below target, which is set by your cyanuric acid. Check the right target in the FC/CYA chart first, confirm your gallons with the pool volume chart, then let the chlorine calculator size the exact dose. When you are clearing algae or combined chlorine, the shock calculator handles the bigger jump to shock level.
Keep this chart at the equipment pad, dose in small steps, and retest. Steady, measured chlorine is what keeps water clear, safe, and easy on your pool.
Frequently Asked Questions
How much liquid chlorine raises free chlorine by 1 ppm?
About 10.7 fluid ounces of 12.5 percent liquid chlorine raises free chlorine by 1 ppm in 10,000 gallons. For 5,000 gallons it is about 5.3 fluid ounces, and for 20,000 gallons about 21.3 fluid ounces. To raise by 3 ppm, triple those amounts; to raise by 5 ppm, multiply by five. Always retest before adding a second dose.
How much cal-hypo raises free chlorine by 1 ppm?
About 1.8 ounces by weight of 73 percent cal-hypo raises free chlorine by 1 ppm in 10,000 gallons. That is roughly 0.9 ounces for 5,000 gallons and 3.7 ounces for 20,000 gallons. Cal-hypo also adds calcium hardness, so it suits pools that are low on calcium but not pools already near the top of the hardness range.
Should I use liquid chlorine or cal-hypo?
Liquid chlorine (sodium hypochlorite) adds nothing but chlorine and a little salt, making it the cleanest choice for routine dosing and shocking. Cal-hypo is a concentrated granular that stores longer and packs more chlorine per pound, but it raises calcium hardness and must be pre-dissolved or broadcast carefully. Neither adds cyanuric acid, so both are good for shocking.
Can I just pour chlorine straight into the pool?
Liquid chlorine can be poured slowly around the deep end with the pump running so it disperses fast. Cal-hypo granules should be broadcast over the surface or pre-dissolved in a bucket of pool water first, since undissolved granules can settle and bleach a vinyl liner or stain plaster. Never pour chemicals near skimmers or returns, and always run the pump while dosing.
How long until I can retest after adding chlorine?
Run the pump and wait at least 20 to 30 minutes for the chlorine to circulate fully, then test free chlorine. For a larger shock dose, give it an hour or more. Retesting before adding more prevents overshooting. If you cannot swim yet, free chlorine is likely still above the comfortable range; wait until it falls back to your target.
Why does my pool need different chlorine amounts than my neighbor?
Dosing depends on pool volume and on how much your free chlorine needs to rise, which in turn depends on your cyanuric acid level. A bigger pool, a lower starting chlorine, or higher CYA all call for more chlorine. Always start from your actual gallons and your CYA-based target rather than copying someone else, since their pool likely differs on both.
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