Target ranges to aim for
Standard residential pool water targets
| Reading | Ideal range | Acts fast or slow |
|---|---|---|
| Free chlorine | 2 to 4 ppm (1 to 3 ppm salt pools) | Fast |
| pH | 7.4 to 7.6 | Fast |
| Total alkalinity | 80 to 120 ppm | Slow, buffers pH |
| Cyanuric acid (stabiliser) | 30 to 50 ppm (60 to 80 salt) | Very slow, only leaves with water |
| Calcium hardness | 200 to 400 ppm | Slow |
| Salt (chlorine generator) | 2,700 to 3,400 ppm | Slow |
The dosing formula
Dose = Rate per 10,000 gal x (Pool gallons / 10,000) x Change wanted
Example: 19,150 gallon pool, chlorine up 2 ppm at 10.7 fl oz per ppm per 10,000 gal = 10.7 x 1.915 x 2 = 41 fl oz of 12.5 percent liquid chlorine.
Do not know your gallons yet? Work it out first on the pool volume calculator. Everything below fails without that number.
Chlorine dosing chart
Amount needed to raise free chlorine by 1 ppm per 10,000 US gallons
| Product | Strength | Dose for 1 ppm |
|---|---|---|
| Liquid chlorine | 12.5 percent | 10.7 fl oz |
| Liquid chlorine | 10 percent | 13.4 fl oz |
| Household bleach | 6 percent | 22 fl oz |
| Cal hypo | 73 percent | 1.8 oz by weight |
| Dichlor | 56 percent, stabilised | 2.4 oz by weight |
| Trichlor tablet | 90 percent, stabilised | 1.5 oz dissolved slowly |
Dichlor and trichlor both add cyanuric acid. Every 10 ppm of chlorine from dichlor adds roughly 9 ppm of stabiliser, which is why heavy tablet users end up locked at high CYA and weak chlorine.
Shock dosing
Shocking means raising free chlorine to about 10 times your combined chlorine reading, or to a breakpoint level of roughly 10 ppm for routine work. For an algae recovery, hold a higher level based on your stabiliser reading until the water clears.
| Situation | Target free chlorine | Liquid chlorine per 10,000 gal |
|---|---|---|
| Weekly maintenance shock | 5 ppm | 54 fl oz of 12.5 percent |
| After heavy bather load | 10 ppm | 107 fl oz |
| Green algae recovery | 20 to 30 ppm held | 2 to 3 gallons over the day |
| Black algae or mustard | 30 ppm plus brushing | 3 gallons plus daily top ups |
Work out the exact bottle count on the pool shock calculator, and match the product on the pool chlorine calculator.
pH and alkalinity dosing
Per 10,000 US gallons
| Goal | Product | Dose |
|---|---|---|
| Raise pH 0.2 | Soda ash | 6 oz by weight |
| Lower pH 0.2 | Muriatic acid 31.45 percent | 12 fl oz |
| Lower pH 0.2 | Dry acid (sodium bisulfate) | 12 oz by weight |
| Raise alkalinity 10 ppm | Baking soda | 1.5 lb |
| Lower alkalinity 10 ppm | Muriatic acid, poured in one spot | 26 fl oz |
Alkalinity and pH move together, so fix alkalinity first and let pH settle before adjusting it. The pool alkalinity calculator, pool pH calculator and muriatic acid calculator handle the arithmetic for your exact volume.
Stabiliser, calcium and salt
| Goal | Product | Dose per 10,000 US gallons |
|---|---|---|
| Raise cyanuric acid 10 ppm | Stabiliser granules | 13 oz by weight |
| Raise calcium hardness 10 ppm | Calcium chloride 77 percent | 1.1 lb |
| Raise salt 1,000 ppm | Pool salt | 83 lb |
| Raise salt from 0 to 3,200 ppm | Pool salt | 267 lb |
Only draining lowers stabiliser and calcium, so add both slowly and retest. Salt figures are on the pool salt calculator and stabiliser on the pool stabilizer calculator.
The safe order to add chemicals
- Test the water and write down every reading.
- Adjust total alkalinity with baking soda or acid. Wait 6 hours with the pump running.
- Retest and adjust pH into 7.4 to 7.6.
- Adjust calcium hardness if it is below 200 ppm.
- Add stabiliser if cyanuric acid is under 30 ppm. Allow up to a week to fully dissolve.
- Add chlorine or shock last, after dark where possible.
- Run the pump for one full turnover, then retest before touching anything else.
Never combine chlorine and acid, even in an empty bucket. Never add water to acid. Add chemicals to the pool with the pump running, spread around the deep end, and keep swimmers out until free chlorine is back under 4 ppm.
Dose examples for three common pools
Raising free chlorine by 2 ppm with 12.5 percent liquid chlorine
| Pool | Gallons | Dose |
|---|---|---|
| 24 ft round above ground | 13,536 | 29 fl oz |
| 16 x 32 ft inground | 19,150 | 41 fl oz |
| 20 x 40 ft inground | 29,922 | 64 fl oz |
Same pools, raising alkalinity by 20 ppm with baking soda: 4.1 lb, 5.7 lb and 9.0 lb. The rate never changes, only your volume does, which is the whole point of measuring it once and keeping it.
Related video
pool chemical dosing FAQs
How much chlorine do I add per 10,000 gallons?
About 10.7 fl oz of 12.5 percent liquid chlorine raises free chlorine by 1 ppm per 10,000 US gallons. With 6 percent household bleach you need about 22 fl oz.
What order should I add pool chemicals in?
Alkalinity first, then pH, then calcium and stabiliser, then chlorine last. Wait about six hours between the alkalinity and pH steps with the pump running.
How long after adding chemicals can I swim?
Wait until free chlorine is back under 4 ppm and pH is in the 7.4 to 7.6 range. After acid or alkalinity changes, allow at least four hours of circulation.
Why does my chlorine not hold?
Usually high cyanuric acid from tablets, or sunlight with no stabiliser at all. Test cyanuric acid first, since chlorine demand rises steeply once it passes about 80 ppm.
Can I dose using pool size instead of gallons?
No. Two pools of the same footprint can differ by 30 percent on depth alone, so all dose rates are written per volume, not per size.
More pool guides
- Pool Volume Formula for Every Pool Shape
All the pool volume formulas, the constants behind them, and a worked example for each shape.
- Average Pool Volume by Pool Type
What a typical pool holds, by type, plus what the average costs to run.
- Pool Volume by Size: Full Gallons Chart
Look up your pool size and read the gallons straight off the chart, no math needed.