Pool pH Calculator
Calculate how much soda ash or muriatic acid your pool needs to reach the right pH.
US Pool pH Dose Reference
| Pool volume | Raise 0.2 pH: pH increaser (lb) | Lower 0.2 pH: muriatic acid (fl oz) |
|---|---|---|
| 5,000 gal | 0.2 lb | 6 fl oz |
| 10,000 gal | 0.4 lb | 12 fl oz |
| 15,000 gal | 0.6 lb | 18 fl oz |
| 20,000 gal | 0.8 lb | 24 fl oz |
| 25,000 gal | 0.9 lb | 30 fl oz |
| 30,000 gal | 1.1 lb | 36 fl oz |
| 35,000 gal | 1.3 lb | 42 fl oz |
| 40,000 gal | 1.5 lb | 48 fl oz |
| 45,000 gal | 1.7 lb | 54 fl oz |
| 50,000 gal | 1.9 lb | 60 fl oz |
Metric Pool pH Dose Reference
| Pool volume | Raise 0.2 pH: soda ash (kg) | Lower 0.2 pH: muriatic acid (mL) |
|---|---|---|
| 20,000 L | 0.09 kg | 177 mL |
| 30,000 L | 0.14 kg | 296 mL |
| 40,000 L | 0.18 kg | 384 mL |
| 60,000 L | 0.27 kg | 562 mL |
| 80,000 L | 0.36 kg | 739 mL |
| 100,000 L | 0.45 kg | 946 mL |
How to Raise Pool pH
To raise pH, use soda ash (sodium carbonate), sold as pH increaser. Test first, calculate the dose above, pre-dissolve only if the label says to, and add it with the pump running. Retest after about 30–60 minutes. Baking soda (sodium bicarbonate) mainly raises alkalinity and is not the right product for a substantial pH increase.
Aeration raises pH by releasing carbon dioxide from the water. Point return jets upward or run a fountain to aerate; this raises pH without adding a chemical, although it does not lower alkalinity.
Muriatic Acid Pool Calculator
Use the calculator above for a muriatic acid pool calculator result tailored to your pool size and pH change. Add acid slowly in front of a return jet, never mix it with chlorine or shock, and retest before adding more.
How to Lower Pool pH
Muriatic acid lowers pH. The amount depends on pool volume, current pH, target pH, and alkalinity, so use the calculated dose as a starting estimate and follow the product label. Wear eye and skin protection, provide ventilation, and add acid to water—not water to acid. Keep swimmers out while adding it and wait at least 30 minutes with circulation before swimming; confirm the pH is in range first.
What Is the Ideal Pool pH Level?
The ideal pool pH is 7.4–7.6. pH and total alkalinity affect one another, so use the Pool Alkalinity Calculator when alkalinity also needs adjustment. When pH is high, chlorine becomes less effective, so keeping pH in range helps sanitizer performance.
Pool pH Recommendations by Brand
| Brand | Suggested pH range | Official explanation |
|---|---|---|
| Pentair | 7.2–7.6 | Pentair water chemistry guidance |
| Hayward | 7.2–7.8 | Hayward water chemistry guide |
| Clorox | 7.2–7.6 | Clorox pool care pH guidance |
| HTH | 7.2–7.8 | HTH pool care water balance guidance |
Frequently Asked Questions
What should my pool pH be?
The ideal pool pH is 7.4–7.6. This range is comfortable for swimmers and helps chlorine work effectively.
Does baking soda raise pH?
No. Baking soda (sodium bicarbonate) mainly raises total alkalinity. Use soda ash (sodium carbonate) when you need to raise pool pH.
How long after adding muriatic acid can I swim?
Wait at least 30 minutes after adding muriatic acid, with the pump circulating, and follow the product label and your test results before swimming.
How do I lower pH without muriatic acid?
Aeration can raise pH without adding chemicals, but it cannot lower pH. To lower pH, use a labeled dry-acid product or muriatic acid according to its instructions.
Why does my pool pH keep rising?
pH can keep rising because of aeration, new plaster or concrete, high alkalinity, or sources of carbon dioxide loss such as waterfalls and water features.
Can I add pH increaser and shock at the same time?
Do not add them together. Adjust pH first, circulate the water, and add shock separately according to both product labels.
What happens if pool pH is too high?
High pH can make chlorine less effective, cause cloudy water and scale, and irritate eyes and skin.
What happens if pool pH is too low?
Low pH can irritate swimmers, damage surfaces and equipment, and make the water corrosive.