Pool Alkalinity Calculator

The ideal total alkalinity (TA) range is 80–120 ppm for most pools. The APSP and most pool professionals recommend 80–120 ppm as the target range. TA below 80 ppm causes pH to swing unpredictably (pH bounce), while TA above 120 ppm makes it difficult to adjust pH and can contribute to scale formation.

Add sodium bicarbonate (baking soda) to raise total alkalinity. Approximately 1.5 lbs of baking soda raises TA by 10 ppm in a 10,000-gallon pool. Pre-dissolve in a bucket of water, then pour around the pool perimeter with the pump running. Retest after 6 hours. Dose in increments; raise no more than 20–30 ppm at a time.

Lower total alkalinity with muriatic acid (hydrochloric acid) or dry acid (sodium bisulfate). Add acid in a concentrated stream to one spot in the deep end with the pump off, let it sit 30 minutes, then turn the pump on. This "column method" preferentially drives down TA more than pH. Retest and repeat as needed. Aeration after treatment helps recover pH if it dropped too far.

Total alkalinity acts as a pH buffer. It resists rapid pH swings caused by rain, bather load, or chemical additions. Without adequate TA, pH becomes unstable ("pH bounce"), which affects chlorine effectiveness and swimmer comfort. TA also plays a role in the Langelier Saturation Index (LSI), which determines whether water is scale-forming or corrosive.

Baking soda (sodium bicarbonate) primarily raises total alkalinity with a modest effect on pH. It raises pH by roughly 0.1–0.2 units per treatment at typical doses. Soda ash (sodium carbonate) is the better choice if you want to raise pH significantly. Use baking soda when TA is low and pH is already near the target range.