Muriatic Acid Calculator

How the muriatic acid calculator works

Acid neutralizes the carbonates that hold your pH up. The more alkalinity in the water, the more acid it takes to move pH the same amount.

You can target pH or target alkalinity, and the tool handles both. Dropping alkalinity always drags pH with it, so plan to aerate afterward.

The formula, step by step

Fluid Ounces = pH Drop / 0.4 x 26 x (Alkalinity / 100) x (Gallons / 10,000)

• Work out how far you want pH to fall.
• 26 fluid ounces per 10,000 gallons drops pH about 0.4 at 100 ppm alkalinity.
• Scale that rate by your real alkalinity reading.
• Scale again by your pool volume.

Worked example

A 30,000 gallon pool reads pH 7.9 with 110 ppm alkalinity, and you want pH 7.5.

Drop = 0.4. Alkalinity factor = 1.1. Size factor = 3.0.

26 x 1.1 x 3.0 = 86 fluid ounces, which is about two thirds of a gallon.

Watch it done

This short video walks through the same job in real life, so you can match what you see on screen to what you do at the pool.

Play video

Tips before you start

Always add acid to water, never water to acid. Pour it slowly along the deep end with the pump running, and keep the jug below your face.

Wear gloves and eye protection, and rinse the deck if any splashes. Acid fumes also corrode metal, so store the jug away from your heater and pump.

Muriatic Acid Calculator FAQs