How much chlorine for a 70,000 litre pool?
The dose for a 70,000 litre pool, worked out from the same chemistry the DoseMyPool app runs. Pick the free chlorine rise you need and read off the product you actually own.
To raise free chlorine by 2 ppm in 70,000 litres
Change the volume or the readings and it recalculates.
Dose table for 70,000 litres
| Free chlorine rise (ppm) | Liquid chlorine 12.5% | Bleach 8.25% | Cal-hypo 73% | Dichlor 56% |
|---|---|---|---|---|
| 0.5 | 280 mL | 388 mL | 48 g | 62 g |
| 1 | 560 mL | 776 mL | 96 g | 125 g |
| 1.5 | 840 mL | 1.16 L | 144 g | 187 g |
| 2 | 1.12 L | 1.55 L | 192 g | 250 g |
| 2.5 | 1.4 L | 1.94 L | 240 g | 312 g |
| 3 | 1.68 L | 2.33 L | 288 g | 375 g |
| 4 | 2.24 L | 3.1 L | 384 g | 500 g |
| 5 | 2.8 L | 3.88 L | 479 g | 625 g |
What changes with the product you pick
Chlorine dose scales with volume and with the rise you want, and nothing else. Two of these products change more than the chlorine: cal-hypo adds calcium hardness, which a plaster pool in hard water does not need, and dichlor adds roughly 0.9 ppm of cyanuric acid for every 1 ppm of chlorine, so it drives stabiliser up fast if you use it all season. Liquid chlorine and bleach leave salt behind and nothing else.
Dosing a 70,000 litre pool
At 70,000 litres a full correction is a lot of product at once. Spread it across the deep end, run the pump through the whole dose, and test only after a full turnover. Big pools also stratify, so one sample from one corner is not the pool.
Safety
- Add chlorine with the pump running, and dose in the evening so a full day of sun does not burn off what you just paid for.
- Wait for one full turnover before testing and adding more.
- Never mix with acid or other chemicals. Add separately.
- Don’t swim until FC is back in range.
Frequently asked questions
How much liquid chlorine does a 70,000 litre pool need?
1.12 L of 12.5% liquid chlorine raises free chlorine by 2 ppm in 70,000 litres. The dose is directly proportional, so half the rise is half the amount.
How much chlorine should a 70,000 litre pool hold?
Target free chlorine is a percentage of your cyanuric acid, not a fixed number. At 40 ppm CYA aim for roughly 3 ppm, and never let it fall below 2.
Can I use household bleach instead?
Yes. It is the same chemical at a lower strength, so you pour more of it, and the table above shows both. Check the label for the percentage, because supermarket bleach varies.
How this is worked out
Every number here comes from the same engine as the DoseMyPool app and the calculator above, run at 70,000 litres. Amounts are estimates: product strengths vary, so follow the label on the bottle you own. See the full method
Other chemicals for 70,000 litres
Other pool volumes
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