NZ & Australia  |  Pool & Spa  |  Free Tool

Pool Chemical
Calculator

Enter your pool volume and current test results to get exact doses for chlorine, pH, and total alkalinity.

Free. No signup required.

2–3 ppm
Ideal free chlorine range
7.2–7.6
Ideal pH range
80–120 ppm
Ideal total alkalinity

Calculate Chemical Doses

Enter your pool size and test readings. The calculator tells you exactly what to add and how much.

Pool Volume

Current Test Results

Use a pool test kit or test strips. Enter the readings from your test.

Target: 2–3 ppm

Target: 7.2–7.6

Target: 80–120 ppm

Pool Water Balance Reference

ParameterIdeal rangeAction
Free chlorine2–3 ppmLow: add granular chlorine
pH7.2–7.6Low: soda ash. High: dry acid
Total alkalinity80–120 ppmLow: sodium bicarbonate
Cyanuric acid (stabiliser)30–50 ppmLow: add stabiliser
Calcium hardness200–400 ppmLow: calcium chloride

Pool Chemistry Tips

Adjust alkalinity first, then pH, then chlorine — in that order
Never mix pool chemicals together — add each one separately
Pre-dissolve granular chemicals in a bucket of pool water before adding
Test more frequently in summer — heat and UV break down chlorine faster
Shock your pool after heavy use, rain, or if chlorine drops below 1 ppm
Run the pump for at least 4 hours after adding chemicals to distribute them

Frequently Asked Questions

What should chlorine levels be in a pool?

Free chlorine should be 2–3 ppm. Below 1 ppm it stops being effective. Above 5 ppm it can irritate skin and eyes.

What is the ideal pH for a pool?

Ideal is 7.2–7.6. At 7.4, chlorine works most efficiently. Below 7.2 is corrosive; above 7.8 chlorine loses effectiveness.

What is total alkalinity and why does it matter?

Total alkalinity buffers your pH against swings. Ideal is 80–120 ppm. Too low and pH jumps with small additions; too high and it becomes hard to adjust.

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