Pool pH Calculator
Calculate how much acid or soda ash to add to bring your pool pH into the ideal range.
Products to Raise pH
Recommended
Soda Ash (Sodium Carbonate)
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Gentler Alternative
Baking Soda (Sodium Bicarbonate)
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Soda ash raises pH with minimal effect on alkalinity. Baking soda raises both pH and alkalinity — use it when both are low. Add with pump running, retest after 4–6 hours.
Products to Lower pH
Recommended
Muriatic Acid (31.45%)
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Alternative
Dry Acid (Sodium Bisulfate)
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Add acid to water, never water to acid. Pour slowly near return jets with the pump running. Wait 4–6 hours before retesting.
Understanding Pool pH
pH measures how acidic or basic your pool water is on a scale from 0 to 14, where 7 is neutral. Pool water should be kept slightly basic, in the 7.2–7.8 range, with 7.4–7.6 being the sweet spot. This range is comfortable for swimmers and allows chlorine to work effectively.
Why pH Matters
- Low pH (below 7.2): Water becomes acidic, causing eye and skin irritation. It corrodes metal equipment, ladders, heater elements, and can etch plaster surfaces.
- High pH (above 7.8): Chlorine effectiveness drops dramatically — at pH 8.0, chlorine is only about 20% effective compared to 65% at pH 7.4. High pH also causes cloudy water and scale buildup on surfaces and equipment.
- The sweet spot (7.4–7.6): Chlorine is active, water is comfortable for swimmers, and equipment is protected from both corrosion and scaling.
The Role of Alkalinity
Total alkalinity acts as a buffer for pH — it determines how easily pH changes. Low alkalinity means pH swings wildly with small amounts of chemical. High alkalinity means pH resists change and requires more acid to lower. This calculator adjusts dosing based on your alkalinity level for more accurate results.
Higher alkalinity = more chemical needed to change pH
Tips for Managing Pool pH
- Always adjust alkalinity BEFORE adjusting pH — alkalinity is the foundation of water balance.
- pH naturally rises in pools over time as CO2 outgasses from the water.
- Test pH at least 2–3 times per week during swimming season.
- Add chemicals with the pump running and retest after 4–6 hours.
- Saltwater pools tend to have rising pH — monitor closely and expect to add acid regularly.
- Rain, heavy bather loads, and chlorine products all affect pH.