Pool Alkalinity Calculator

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

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.