Pool calculatorsWater balance
Pool chemistry calculator
Measure your pool’s chlorine, pH, alkalinity and hardness. We tell you whether the water is balanced (Langelier index) and the exact dose of each chemical to add. The volume is optional: you only need it for the amounts.
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Water analysis
pHiMeasures how acidic the water is. With the right pH, chlorine disinfects well and you avoid irritation and corrosion.7.4
Total alkalinityiActs as a pH buffer: the right alkalinity stops the pH from swinging up or down.100 ppm
Calcium hardnessiAmount of dissolved calcium. Too low makes the water aggressive; too high causes scaling.300 ppm
Stabiliser (cyanuric acid)iProtects chlorine from the sun’s UV so it lasts longer; too much makes it less effective.40 ppm
Free chlorineiChlorine available to disinfect the water and kill bacteria and algae.2.0 ppm
Water temperatureiNot a reactant: it is used to calculate the Langelier index, since warm water scales more easily.25 °C
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Pool volume (optional)
Shape
Depth
Estimated volume: 0 L (0 m³)
Water diagnosis
Water balance index (Langelier)
-0.02Balanced water
CorrosiveBalancedScaling
The water is in balance: neither corrosive nor scaling. This is the ideal state for your pool and equipment.
Your water is balanced! Every parameter is within the recommended range.
pHIn range
Total alkalinityIn range
Calcium hardnessIn range
Stabiliser (cyanuric acid)In range
Free chlorineIn range
Indicative calculation. Doses depend on the actual product concentration: always follow the manufacturer’s instructions and add in several steps, measuring between each dose.
Products to balance the water
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Pool water chemistry calculator
This pool calculator brings the full chemical control of your water into one tool: chlorine, pH, total alkalinity, calcium hardness and stabiliser. Enter your test readings and you instantly know which parameter to correct and how much product to add for your volume.
Chlorine and pH go hand in hand: if the pH climbs, chlorine disinfects far worse no matter how much you add. That is why the tool looks at chlorine and pH together and shows you how to bring both into their ideal range (pH 7.2–7.6 and free chlorine 1–3 ppm).
It also calculates the Langelier Saturation Index to tell you whether the water is corrosive, balanced or scaling — something a plain chlorine reading misses. If you only need to adjust the sanitiser, use our chlorine calculator.
Frequently asked questions
What is the Langelier Saturation Index (LSI)?
It is a value that shows whether water is balanced, corrosive or scaling, combining pH, total alkalinity, calcium hardness and temperature. The ideal range is between −0.3 and +0.3.
In what order should I adjust the water parameters?
First total alkalinity (it stabilises the pH), then pH, then calcium hardness and stabiliser, and finally chlorine. Add products gradually and measure again before correcting further.
What are the ideal pool water values?
pH 7.2–7.6; total alkalinity 80–120 ppm; calcium hardness 200–400 ppm; stabiliser 30–50 ppm and free chlorine 1–3 ppm.
How do I lower hardness or stabiliser if they are high?
There is no product that lowers them directly: the only effective way is to drain part of the water and refill with fresh, lower-concentration water.
How do I calculate the chlorine and pH of a pool?
Measure the free chlorine and pH with a test kit or test strips and enter them into the calculator. The target is free chlorine 1–3 ppm and pH 7.2–7.6; the tool tells you how much product to add to reach each value and keep the water disinfected and balanced.
What is a pool chemical calculator for?
It precisely doses the water products (chlorine, pH, alkalinity, hardness and stabiliser) according to your pool volume, avoiding adding too much or too little and keeping the water healthy and crystal clear.