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Pool chemical levels chart
Here are the usual targets. Official figures are marked, because only some of these numbers come from a health authority and the rest are common practice in pool care.
| Test | Common target | Official or maker figure |
|---|---|---|
| Free chlorine | 2 to 4 ppm | CDC: at least 1 ppm; 2 ppm with CYA |
| pH | 7.2 to 7.6 | CDC: 7.0 to 7.8 |
| Total alkalinity | 80 to 120 ppm | CDC model code: 60 to 180 ppm |
| Calcium hardness | 200 to 400 ppm | CDC model code: under 2,500 ppm |
| Stabilizer (CYA) | 30 to 50 ppm | None for home pools in CDC guidance |
| Salt | 3,200 ppm | Hayward AquaRite: 2,700 to 3,400 ppm |
| Hot tub chlorine | 3 to 5 ppm | CDC: at least 3 ppm |
The CDC model code is written for public pools, so treat its limits as outer bounds for a home pool. If you shock, do not swim until chlorine has dropped: the CDC notes that DPD tests can read falsely low or 0 above 10 ppm.
Test how often?
The CDC advises testing chlorine and pH at least twice a day, and more often when the pool is busy. Many home owners test less, but test before use and after heavy rain or a party. Check alkalinity, calcium and stabilizer every week or two, since they change slowly.
Fix the numbers
Enter your readings in the pool chemical calculator to see what to add.