Pool Alkalinity (Muriatic Acid) Calculator
High total alkalinity causes pH to drift and scale to form. Enter your pool volume and current and target alkalinity to see how much 31.45% muriatic acid to add.
Pool Alkalinity (Muriatic Acid) Calculator
Why use the Pool Alkalinity (Muriatic Acid) Calculator
High total alkalinity makes pH bounce around and scale form on surfaces and equipment. This gives you the acid dose to bring it down without guessing.
How to get your numbers
- Volume in gallons.
- Current total alkalinity from a drop-based test kit (most accurate).
- Target: 80–120 ppm for most pools.
Recommended for this job
How to use it
- Enter your pool volume.
- Enter current total alkalinity from a test kit.
- Enter the target — 80–120 ppm suits most pools.
Frequently asked questions
How much acid do I need to lower alkalinity?
About 25 fl oz of 31.45% muriatic acid per 10,000 gallons lowers total alkalinity by roughly 10 ppm. The calculator scales that to your pool.
Will lowering alkalinity also change pH?
Yes — muriatic acid lowers both. Add it, let it circulate, then re-test and balance pH and alkalinity together over a day or two.
What should pool alkalinity be?
Generally 80–120 ppm. Balance total alkalinity first, because it buffers and stabilizes pH.
What happens if pool alkalinity is too high?
pH becomes hard to adjust and tends to drift up, scale forms on surfaces and equipment, and water can turn cloudy.
How do I raise pool alkalinity?
Add baking soda (sodium bicarbonate). Roughly 1.5 lbs per 10,000 gallons raises total alkalinity about 10 ppm.
Should I fix pH or alkalinity first?
Adjust total alkalinity first — it stabilizes pH, so getting it in range makes pH much easier to hold.
How much muriatic acid can I add at once?
Add it in stages and re-test rather than dumping a large dose. Big single additions can overshoot and drive pH dangerously low.
