Bicarbonate Alkalinity
Bicarbonate alkalinity is the portion of total alkalinity contributed by bicarbonate ions (HCO3-), which is the dominant form in properly maintained pool water.
Definition
Bicarbonate alkalinity is the portion of total alkalinity contributed by bicarbonate ions (HCO3-), which is the dominant form in properly maintained pool water.
Typical Values: At pool pH range (7.2–7.6), >95% of total alkalinity is bicarbonate alkalinity
In Plain Language
Total alkalinity in pool water (at pH 7.2–7.6) consists predominantly of bicarbonate ions. Carbonate and hydroxide alkalinity are negligible at normal pool pH. When a test kit measures total alkalinity, it is effectively measuring bicarbonate alkalinity in a well-maintained pool. Sodium bicarbonate additions directly increase bicarbonate alkalinity.
Why It Matters
Understanding that pool alkalinity is primarily bicarbonate alkalinity explains the chemistry of sodium bicarbonate additions and acid-based reductions.
Typical Values
At pool pH range (7.2–7.6), >95% of total alkalinity is bicarbonate alkalinity
Last reviewed: 2026-06-01