Pool Alkalinity Calculator (Baking Soda to Raise, Muriatic Acid to Lower)
How much baking soda raises your pool's total alkalinity, or how much muriatic acid or dry acid lowers it, for your pool size, using published doses per 10,000 gallons.
Formula
Batches = |target − current| ÷ 10 × gallons ÷ 10,000. Raise: baking soda (lb) = batches × 1.4. Lower: muriatic acid 31.4% (fl oz) = batches × 26, or sodium bisulfate (lb) = batches × 2.1. Additions: raise no more than about 50 ppm at a time; add no more than 1 quart of acid per 10,000 gallons at a time.
Worked example
Inputs: Pool volume = 15000 gal; Current total alkalinity (test result) = 60 ppm; Target total alkalinity (from your pool builder or test kit guide) = 100 ppm.
| Change ppm | 40 |
|---|---|
| Baking soda lb | 8.4 |
| Muriatic acid fl oz | — |
| Muriatic acid quarts | — |
| Sodium bisulfate lb | — |
| Additions | 1 |
Raising: add baking soda (sodium bicarbonate), no more than about 50 ppm at a time, then circulate and retest.
FAQ
How much baking soda raises alkalinity 10 ppm?
1.4 lb per 10,000 gallons. That matches the chemistry: 10 ppm as calcium carbonate in 10,000 gallons (about 83,400 lb of water) is 0.83 lb, and sodium bicarbonate weighs 84 ÷ 50 times as much per unit of alkalinity, so about 1.4 lb.
How much baking soda for a 15,000 gallon pool?
To go from 60 to 100 ppm: 40 ÷ 10 × 1.5 × 1.4 = 8.4 lb, added in one go since it is under 50 ppm. Circulate and retest after.
How much muriatic acid lowers alkalinity?
About 26 fl oz of 31.4% muriatic acid per 10 ppm per 10,000 gallons. Lowering a 20,000 gallon pool from 150 to 100 ppm takes about 260 fl oz (8.1 quarts). With the 1 quart per 10,000 gallons limit that is 5 additions, retesting about 12 hours apart.
Baking soda or soda ash?
Baking soda (sodium bicarbonate) raises alkalinity with only a small pH rise. Soda ash (sodium carbonate) raises pH much more; the Indiana guide says to use soda ash only when both pH and alkalinity are low.
Is muriatic acid safe to handle?
Use eye protection and gloves, always add acid to water (never water to acid), never mix chemicals, and keep swimmers out while adjusting. Follow the label.
Sources
Related
- Pool Liquid Chlorine Calculator (Ounces to Raise Free Chlorine)
- Pool Volume Calculator: Rectangular (Gallons)
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- Pool Stabilizer (Cyanuric Acid) Calculator: How Much to Add or Drain
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Last reviewed 2026-10-20.