Sodium Bisulfate
Sodium bisulfate (dry acid) is a granular acid used to lower pool pH and total alkalinity as a safer alternative to liquid muriatic acid.
Definition
Sodium bisulfate (dry acid) is a granular acid used to lower pool pH and total alkalinity as a safer alternative to liquid muriatic acid.
Typical Values: Purity: 93.2% NaHSO4; Lowers pH similarly to muriatic acid but at higher cost per effective dose
In Plain Language
Sodium bisulfate is sold as pH Down or Dry Acid. It is less hazardous to handle than muriatic acid and does not produce fumes. However, it is more expensive per effective dose. When dissolved in water, it produces sulfuric acid, which has the same effect on pool chemistry as muriatic acid. Pre-dissolve in a bucket of water before adding to the pool.
Why It Matters
Dry acid is the preferred pH reducer for applications where liquid acid handling is impractical or where chemical storage safety is a concern.
Typical Values
Purity: 93.2% NaHSO4; Lowers pH similarly to muriatic acid but at higher cost per effective dose
Last reviewed: 2026-06-01