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Pool Water Chemistry Targets
Maintaining balanced pool chemistry keeps water safe, clear, and prevents equipment damage. Test weekly during swim season and after heavy rain or heavy use.
| Parameter | Target Range | Low Risk | High Risk |
|---|---|---|---|
| Free Chlorine | 1–3 ppm | Algae, bacteria | Eye irritation |
| pH | 7.4–7.6 | Corrosion, irritation | Cloudy, Cl loss |
| Total Alkalinity | 80–120 ppm | pH instability | Scale, cloudy |
| Calcium Hardness | 200–400 ppm | Plaster etching | Scale deposits |
Frequently Asked Questions
The ideal pool pH is 7.4 to 7.6. Below 7.2 causes eye and skin irritation and corrodes metal equipment. Above 7.8 reduces chlorine effectiveness by up to 90% and causes cloudy water and scale formation.
About 1 ounce of granular chlorine (calcium hypochlorite, 68%) per 10,000 gallons raises free chlorine by roughly 0.7 ppm. For liquid chlorine (10%): about 13 oz per 10,000 gallons per ppm needed.
Sodium bicarbonate (baking soda) raises total alkalinity. 1.4 lbs per 10,000 gallons raises alkalinity by approximately 10 ppm. Always adjust alkalinity before adjusting pH.
Muriatic acid or sodium bisulfate (dry acid) lower pH. Muriatic acid (31.45%): about 1 quart per 10,000 gallons lowers pH by about 0.2 units. Always add acid to water, never water to acid.
Add calcium chloride. About 1.25 lbs per 10,000 gallons raises calcium hardness by 10 ppm. Dissolve in a bucket of water first before adding to the pool.
After adding chlorine: wait 30 minutes. After adding acid (pH down): wait 30 minutes with pump running. After shocking: wait until chlorine drops below 3 ppm (usually 8–24 hours depending on shock level).