PoolDose How much salt to add to a salt water pool
Each g/l you need to add takes 1 kg of salt per cubic metre of water. Taking a 50 m³ pool from 1.5 to 4.5 g/l is 150 kg. The Salt (salt chlorinator) product in Dosing does this, and shows ppm instead of g/l when you use US units.
How is the salt dose calculated?
A cubic metre is 1,000 litres, and 1 g/l across 1,000 litres is 1,000 g. So kilograms of salt equal cubic metres times the rise in g/l. In ppm, 1 g/l is 1,000 ppm. The app converts the ppm you type in US mode, then shows pounds or ounces.
How do I get the salt dose in PoolDose?
- Set the pool volume in Volume or type it into the volume field in Dosing.
- Open Dosing and pick Salt (salt chlorinator).
- Enter Measured salt (g/l) from your salt meter or strip, and Target salt (g/l). In US mode the labels read ppm.
- Read the weight under Dose.
| Pool | From to | Dose |
|---|---|---|
| 50 m³ | 0 to 4.5 g/l | 225.00 kg |
| 50 m³ | 1.5 to 4.5 g/l | 150.00 kg |
| 50 m³ | 3.0 to 4.5 g/l | 75.00 kg |
| 13,000 gal (US units) | 1,500 to 3,200 ppm | 184.43 lb |
What does the result mean in practice?
The result switches to pounds once it passes 16 oz in US mode and to kilograms from 1,000 g in metric, so 225.00 kg is a big job: nine sacks if you buy them in 25 kg. Check the sack size you can get before you plan the day.
The salt number only means something if your reading does. Meters and strips differ from one another, so test again once the salt has dissolved and circulated, and before you add more.
Which target should I type?
Use the number in your salt chlorinator's manual. Different cells ask for different levels, and the app has no table of them. Manuals commonly quote a figure around 3 to 4 g/l (3,000 to 4,000 ppm) or a little higher, but read yours.
| Metric (g/l) | US (ppm) |
|---|---|
| 3.0 | 3,000 |
| 3.5 | 3,500 |
| 4.0 | 4,000 |
| 4.5 | 4,500 |
The app converts ppm to g/l by dividing by 1,000, so the dose is the same either way. As a quick check in US units, a 10,000 gallon pool needs about 83.5 lb of salt for each 1,000 ppm you add.
How do I add the salt and check it?
- Switch the chlorinator off if its manual says to, and run the pump.
- Add the salt in portions, spread around the pool as the manual says, and brush it so it dissolves instead of sitting on the floor.
- Let the pump circulate for the time your chlorinator manual gives before you measure. Undissolved salt gives a false low reading.
- Measure again, type the new value as Measured salt (g/l) and read what is still missing. The dose shrinks to the remaining gap.
Add only about three quarters of a big dose first. Pushing a pool over its target is much harder to fix than being a little short, because the app cannot lower salt and the only remedy is draining part of the water and refilling.
What are the limits of the salt dose?
- The dose assumes pure salt. It does not account for salt already in your fill water beyond the measured value you type.
- It is for chlorinator pools. Nothing in the app removes salt; for too much salt, partial draining is the only fix.
- Use the kind of salt your chlorinator manual asks for. Plain pool salt without additives is the usual advice, but the app does not check it.
Questions and answers
How much salt raises a pool by 1000 ppm?
What ppm should my salt pool be?
Does the app work in gallons for salt?
Can it lower salt?
Why is my measured salt reading different from the dose?
More PoolDose guides
- How much chlorine to add to a pool
- How to calculate pool volume in gallons or litres
- How much acid to lower pool pH
- Pool LSI calculator: is your water aggressive or scaling?
- What order to balance pool chemicals
- A pool water test log, with a test strip scanner
- All questions about PoolDose
- Back to PoolDose