Muriatic Acid Dosage Calculator
This calculator estimates the amount of muriatic acid (hydrochloric acid) needed to lower the Total Alkalinity (TA) in your pool or spa water. Reducing TA will also lower pH. Always handle muriatic acid with extreme care.
Using Muriatic Acid Safely
Muriatic acid (a form of Hydrochloric Acid, HCl) is a hazardous chemical. It is effective for lowering Total Alkalinity and pH in swimming pools and spas.
- Safety Gear: ALWAYS wear appropriate personal protective equipment (PPE), including acid-resistant gloves, eye protection (goggles or face shield), and clothing that covers your skin. Work in a well-ventilated area.
- Dilution: ALWAYS add acid to water, never water to acid. This helps prevent splashing and a potentially violent reaction. When adding to a pool, pre-dilute the acid in a bucket of pool water (add acid slowly to the water in the bucket).
- Application: Pour the diluted acid solution slowly into the deep end of the pool, away from skimmers and fittings, or distribute it around the pool. Allow the pump to run for several hours to circulate.
- Retest: Wait at least 4-6 hours (preferably longer) after adding acid and before retesting the water. Make adjustments in small increments.
- Storage: Store muriatic acid in its original, clearly labeled container, tightly sealed, in a cool, dry, well-ventilated area, away from children, pets, and incompatible materials (like chlorine).
How Dosage is Estimated
This calculator uses a common guideline: approximately 20 fluid ounces (1.25 pints) of 31.45% muriatic acid per 10,000 gallons of water will lower Total Alkalinity by about 10 ppm. The actual amount can vary based on water temperature, other dissolved solids, and the specific acid product used.
The calculation adjusts for your specific pool volume, desired TA drop, and the strength of the muriatic acid you are using. Remember that lowering TA will also lower pH. You may need to aerate the water or use a pH increaser if pH drops too low after TA is in range.