Pool salt calculator
Enter your current salt reading and your chlorinator’s target. You’ll get pounds, kilograms and whole bags, plus how much to drain if you overshot.
Add this much salt
Add about 80–90% first. Salt readings on a cell can lag and differ from a test strip; retest after 24 hours of circulation, then top up.
Adding salt the right way
- Use pool salt: 99%+ pure sodium chloride, no anti-caking agents or iodine.
- Pump on, chlorinator off. Pour salt around the shallow end and perimeter, not into the skimmer.
- Brush undissolved salt toward the main drain. Run the pump 24 hours, then test.
Bags of salt by pool size (from zero)
| Gallons | 2,700 ppm | 3,200 ppm | 3,400 ppm |
|---|---|---|---|
| 5,000 | 113 lb · 3 bags | 134 lb · 4 bags | 142 lb · 4 bags |
| 10,000 | 225 lb · 6 bags | 267 lb · 7 bags | 284 lb · 8 bags |
| 15,000 | 338 lb · 9 bags | 401 lb · 11 bags | 426 lb · 11 bags |
| 20,000 | 451 lb · 12 bags | 534 lb · 14 bags | 567 lb · 15 bags |
| 25,000 | 563 lb · 15 bags | 668 lb · 17 bags | 709 lb · 18 bags |
| 30,000 | 676 lb · 17 bags | 801 lb · 21 bags | 851 lb · 22 bags |
| 40,000 | 901 lb · 23 bags | 1,068 lb · 27 bags | 1,135 lb · 29 bags |
How a salt pool makes chlorine
A salt chlorinator passes a low-voltage current through a cell of coated titanium plates. Chloride in the water is converted into chlorine, which sanitizes and eventually reverts to chloride. That’s why salt isn’t used up; it only leaves when water splashes out, backwashes or drains.
The cell also produces hydrogen bubbles, which drive carbon dioxide out and push pH up. Salt pools usually need regular acid and do best with alkalinity around 60–80 ppm and stabilizer around 60–80 ppm (Hayward and Pentair manuals list their own ranges).
Questions pool owners ask
How much salt do I add to my pool?
Multiply the ppm you need to add by your gallons and by 0.0000834 to get pounds. Going from 0 to 3,200 ppm in 15,000 gallons takes about 400 lb (ten 40 lb bags). Always check your chlorinator’s manual for its target.
What salt level should my pool be?
Most residential salt cells want 2,700–3,400 ppm with an ideal around 3,200 ppm (Hayward AquaRite), or roughly 2,700–3,400 ppm for many Pentair IntelliChlor models. Some low-salt systems run lower. Use the number in your own manual.
How many bags of salt for a new pool?
For 3,200 ppm: about 7 bags (40 lb) for 10,000 gallons, 10 bags for 15,000, 14 bags for 20,000 and 20 bags for 30,000 gallons. Start with 80–90% of that, wait 24 hours, test, then top up.
How long after adding salt can I turn on the chlorinator?
Brush the salt around and run the pump for about 24 hours so it fully dissolves and mixes before trusting the cell’s salt reading or turning up production. Many manuals say to leave the cell off while salt dissolves.
How do I lower salt in my pool?
Salt doesn’t evaporate or get used up, so the only way to lower it is to drain some water and refill with fresh. The calculator shows what share to replace.