Free tool

Pool chemical dosing calculator

Q: How much liquid chlorine do I add per ppm?

With 12.5% liquid chlorine, raising free chlorine by 1 ppm takes about 10.24 fluid ounces per 10,000 gallons. Scale by your pool's volume: a 15,000-gallon pool needs about 15.4 oz per ppm.

Q: How much muriatic acid lowers pH by 0.1?

As a rule of thumb, about 6 fluid ounces of 31.45% muriatic acid lowers pH by 0.1 in 10,000 gallons, though alkalinity affects the real response. Add acid in stages and retest.

Q: Why does the calculator refuse some readings?

Readings outside the physically plausible range of a test kit, like a pH of 78, are flagged as implausible instead of dosed. A typo should produce a warning, never a dangerously large chemical amount. Our field app applies the same guard.

Enter your pool's volume and whatever readings you have. You'll get doses scaled to your exact gallons, using the same fail-closed math the FieldTechScheduler app computes poolside for professional techs. Leave any reading blank to skip it.

Pool volume (gallons)

Free chlorine (ppm, target 1–4)

pH (target 7.4–7.6)

Alkalinity (ppm, target 80–120)

CYA (ppm, target 30–50)

Salt (ppm, target 2700–3400)

Use judgment, not just arithmetic. These are reference doses for typical residential pools with common products (12.5% liquid chlorine, 31.45% muriatic acid, cyanuric acid stabilizer). Add in stages, keep the pump running, retest before re-dosing, and never mix chemicals with each other. Alkalinity, temperature, and CYA all shift real-world response.

How the math works

Every dose is the same three-step calculation our field app runs:

Distance to target. How far is your reading from the middle of the target band? FC at 0.8 against a 1–4 ppm target is 1.7 ppm short of the 2.5 midpoint.
Reference amount. Each product has a known effect per step per 10,000 gallons. For example, 10.24 oz of 12.5% liquid chlorine raises FC by 1 ppm in 10,000 gallons.
Scale to your pool. Multiply by your gallons ÷ 10,000. That 1.7 ppm correction needs ~17 oz in 10,000 gallons, ~22 oz in 12,500.

And one guard: a reading outside a test kit's physically plausible range (pH typed as 78, FC at 50 ppm) is refused, not dosed. A typo should produce a warning, never a bucket of acid. Read the full write-up of the dosing math →

Frequently asked questions

How much liquid chlorine do I add per ppm?

With 12.5% liquid chlorine, about 10.24 fl oz per ppm per 10,000 gallons. A 15,000-gallon pool needs about 15.4 oz per ppm.

How much muriatic acid lowers pH by 0.1?

Roughly 6 fl oz of 31.45% muriatic acid per 0.1 pH per 10,000 gallons, though alkalinity affects the real response. Add in stages and retest.

Why does the calculator refuse some readings?

Readings outside a test kit's plausible range are flagged as implausible instead of dosed. A typo should produce a warning, never a dangerously large amount. Our field app applies the same guard.

Run a pool route for a living?

This math runs automatically on every stop in FieldTechScheduler: offline, per body of water, checked against truck stock.

See the pool service app