Pool chlorine dosing calculator
Chlorine products differ enormously in strength. The dose is the concentration change times the volume, divided by the available chlorine.
ppm
ppm
ppm
Product to add
800g
- In kilograms
- 0.800
- If liquid, roughly this volume
- 0.67
- Chlorine increase
- 2.50 ppm
- Minimum free chlorine for your stabiliser level About 7.5% of the cyanuric acid level.
- 3.00 ppm
- Shock level
- 16.0 ppm
- Product needed to shock
- 4960
- Target is above the minimum
- 1
Show the working
- Pool volume = 40 000
- Current free chlorine = 0.5
- Target free chlorine = 3
- Product = 12.5
- Cyanuric acid = 40
- Chlorine increase = max(3 - 0.5, 0) = 2.5
- grams_pure = 40 000 * 2.5 / 1000 = 100
- Product to add = 12.5 > 0 ? 100 / (12.5/100) : 0 = 800
- In kilograms = 800 / 1000 = 0.8
- If liquid, roughly this volume = 800 / 1200 = 0.666 667
- Minimum free chlorine for your stabiliser level = 40 * 0.075 = 3
- Shock level = 40 * 0.4 = 16
- Product needed to shock = 12.5 > 0 ? 40 000 * max(16 - 0.5, 0) / 1000 / (12.5/100) : 0 = 4960
- Target is above the minimum = 3 >= 3 ? 1 : 0 = 1
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
Scenarios & local history
Compare a saved scenario
Recent calculations
The formula
- grams of available chlorine = volume in litres x ppm change / 1000
- product weight = that divided by the available chlorine fraction
Cyanuric acid protects chlorine from sunlight but also binds it. The higher the stabiliser, the more free chlorine you need for the same sanitising power.
Never mix chlorine products, and never add water to concentrated chemicals. Add chemicals to water.