Muriatic Acid
Muriatic acid (dilute hydrochloric acid) is the most commonly used chemical for lowering pool pH and total alkalinity.
Definition
Muriatic acid (dilute hydrochloric acid) is the most commonly used chemical for lowering pool pH and total alkalinity.
Typical Values: Concentration: 31.45% (pool grade); pH in solution: strongly acidic (0.1–0.5)
In Plain Language
Pool-grade muriatic acid is sold at approximately 31.45% concentration (20 Baumé). It is a strong acid that must be handled with appropriate protective equipment (eye protection, acid-resistant gloves). Always add acid to water (not water to acid) to prevent spattering. After adding muriatic acid to the pool, allow 30–60 minutes of pump circulation before retesting pH.
Why It Matters
Muriatic acid is the most economical and effective pH reducer and alkalinity reducer for pools.
Typical Values
Concentration: 31.45% (pool grade); pH in solution: strongly acidic (0.1–0.5)
Last reviewed: 2026-06-01