Chlorine Dosage Calculator Australia
Work out how much chlorine to add by pool volume and free chlorine reading. The calculator below covers liquid chlorine (sodium hypochlorite) and granules.
Chlorine dose calculator
Enter your pool volume, current free chlorine reading and target level to estimate the dose.
Add about 800 ml of liquid chlorine 12.5%
Raises free chlorine from 1.0 to 3.0 ppm (2.0 ppm lift).
Estimate only — always follow the product label. With the pump running, add chlorine to the deep end and never mix chlorine with acid or other chemicals.
How much liquid chlorine to add
Most Australian pool liquid chlorine is around 10–12.5% sodium hypochlorite. The chart below uses 12.5% as a practical estimate. Always check the label strength on your bottle.
| Pool volume | Raise FC by 1 ppm | Raise FC by 2 ppm |
|---|---|---|
| 30,000 L | 240 ml | 480 ml |
| 50,000 L | 400 ml | 800 ml |
| 75,000 L | 600 ml | 1.2 L |
| 100,000 L | 800 ml | 1.6 L |
Example: a 50,000 L pool reading 0.5 ppm FC that needs 2.5 ppm needs about a 2 ppm lift → roughly 800 ml of 12.5% liquid chlorine.
Granular chlorine dose chart (70%)
For 70% available chlorine granules (calcium hypochlorite or dichlor — check the label), the same 1 ppm lift needs fewer grams:
| Pool volume | Raise FC by 1 ppm | Raise FC by 2 ppm |
|---|---|---|
| 30,000 L | 43 g | 86 g |
| 50,000 L | 71 g | 143 g |
| 75,000 L | 107 g | 214 g |
| 100,000 L | 143 g | 286 g |
Chlorine tablets maintain the level but raise it slowly. Use liquid or granular chlorine for a quicker increase. If you need to treat algae, see the pool shock calculator.
Target free chlorine ranges
- Traditional chlorinated / saltwater: usually 1–3 ppm free chlorine
- Freshwater / Naked: usually 0–0.5 ppm residual chlorine (copper does most of the sanitising)
If you are unsure which system you have, start with the pool chemical calculator and select your water type.
Safe dosing steps
- Test free chlorine, pH, and alkalinity first.
- Balance pH near 7.2–7.6 so chlorine works properly.
- Calculate the dose from the calculator or chart above.
- With the pump running, add chlorine slowly to the deep end.
- Never mix liquid chlorine with acid or put acid in the same container.
- Retest after circulation and again the next day.
When liquid chlorine is the right fix
- Free chlorine is low after heavy swimming or a heatwave
- Salt chlorinator cannot keep up after rain or a party
- You need a quick FC boost before shocking for algae
For cloudy water or algae, also read the troubleshooting guide and algae types explained.
Chlorine calculator FAQs
How much chlorine do I add to my pool in Australia?
Subtract your free chlorine reading from your target (usually 1–3 ppm for chlorinated or saltwater pools) to find the increase you need. In a 50,000 L pool, 400 ml of 12.5% liquid chlorine or about 71 g of 70% granular chlorine raises free chlorine by 1 ppm. The calculator above estimates the dose for your pool.
How much liquid chlorine do I add to a 50,000L pool?
For common 12.5% liquid chlorine, about 400 ml raises free chlorine by roughly 1 ppm in a 50,000 L pool. Use the chlorine dose calculator on this page for liquid dosing. The main calculator estimates granular chlorine doses for Amazon Australia products.
What free chlorine level should Australian pools target?
Traditional chlorinated and saltwater pools usually target about 1–3 ppm free chlorine. Freshwater or Naked systems target much lower residual chlorine (often 0–0.5 ppm).
Can I use liquid chlorine in a saltwater pool?
Yes. Liquid chlorine is useful for a quick free chlorine boost when the salt chlorinator cannot keep up after heavy use, rain, or algae.
Related dosing tools
Buying chlorine in Australia
Liquid chlorine (10–12.5% sodium hypochlorite) is usually sold at pool shops and hardware stores. Granular chlorine, dichlor granules, and tablets are available on Amazon Australia. For doses matched to those products, use the main pool calculator.
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