Pool Alkalinity Calculator

Calculate how much baking soda or acid to add to raise or lower your pool's total alkalinity.

Just need baking soda? Try our dedicated baking soda calculator with results in lbs, oz, and cups.

Ideal range: 80–120 ppm Saltwater: 80–100 ppm
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Pool Type

Understanding Pool Total Alkalinity

Total alkalinity (TA) measures the water's ability to buffer pH changes. Think of it as a shock absorber for your pH — when alkalinity is in the right range, pH stays stable. When it's off, pH bounces around and becomes difficult to manage.

Ideal Alkalinity Levels

  • Regular chlorine pools: 80–120 ppm — this range keeps pH stable and prevents corrosion or scaling. A target of 100 ppm is ideal for most pools.
  • Saltwater pools: 80–100 ppm — saltwater generators tend to raise pH over time, so keeping alkalinity slightly lower helps counteract this effect. A target of 90 ppm works well.
  • Below 60 ppm: Critically low — pH will be very unstable (known as "pH bounce"), and the water can become corrosive to pool equipment and surfaces.
  • Above 180 ppm: Very high — pH will be extremely difficult to lower, water may become cloudy, and scale can form on surfaces and equipment.

The Dosing Formulas

To raise alkalinity with baking soda (sodium bicarbonate):

lbs of baking soda = (Pool Gallons × PPM Increase) ÷ 10,000 × 1.5

As a rule of thumb, 1.5 pounds of baking soda raises 10,000 gallons by approximately 10 ppm.

To lower alkalinity with muriatic acid (31.45%):

quarts of muriatic acid = (Pool Gallons × PPM Decrease) ÷ 10,000 × 0.25

As a rule of thumb, 0.25 quarts (8 fl oz) of muriatic acid lowers 10,000 gallons by approximately 10 ppm.

Tips for Adjusting Alkalinity

  • Always adjust alkalinity BEFORE adjusting pH — alkalinity changes affect pH, but not the other way around.
  • Add baking soda by broadcasting it across the pool surface with the pump running for even distribution.
  • Retest alkalinity after 6 hours to allow full circulation and mixing.
  • Rain and heavy bather load can lower alkalinity over time.
  • Alkalinity and pH are linked — raising alkalinity will also raise pH slightly, and adding acid to lower alkalinity will also lower pH.
  • When adding acid, pour it in one spot with the pump running to create a column of low-pH water. This targets alkalinity more than pH.