A 15,000 gallon pool at 1,000 ppm salt needs 275 pounds of pool salt to reach 3,200 ppm, which is seven 40 lb bags. The calculator above does that sum for your gallons, the level you have now and the level your salt system asks for, and it flips to a drain percentage when the reading is too high. If you do not know your gallons yet, the pool volume calculator gives them, and it is saved for this page.
How the salt is calculated
One ppm is one milligram of salt in a litre of water. In US units, 1 ppm across 1 gallon is 0.0000083454 lb of salt, so:
Salt (lb) = gallons × 0.0000083454 × (target ppm − current ppm)
For 15,000 gal from 1,000 to 3,200 ppm: 15,000 × 0.0000083454 × 2,200 = 275.4 lb. Divide by 40 and round up: 7 bags (4 bags if you buy 80 lb bags). In metric that is 124.9 kg. A single 40 lb bag adds about 320 ppm to 15,000 gal, so the last bag is worth a retest before you open it. The same rule reproduces the Hayward AquaRite manual chart: 10,000 gal from 0 to 3,200 ppm is 267 lb.
Which target ppm to use
Use the number in your own cell's manual. They differ, and we read each one:
| System | Ideal | Range the manual gives |
|---|---|---|
| Hayward AquaRite / T-Cell | 3,200 ppm | 2,700 to 3,400 ppm |
| Pentair IntelliChlor IC15 to IC60 | 3,400 ppm | 3,000 to 4,500 ppm |
| Pentair IntelliChlor Plus, LT | 3,600 ppm | 2,600 to 4,500 ppm |
| Pentair iChlor | 3,600 ppm | 3,000 to 4,500 ppm |
| CircuPool RJ and SJ | 3,500 ppm | 3,000 to 4,000 ppm |
| Intex Saltwater System | 3,000 ppm | 2,500 to 3,500 ppm |
Many guides quote 3,200 ppm for a Pentair cell and 3,400 ppm for CircuPool. The manuals we read say 3,400 and 3,500, so the presets follow the manuals. If your model is not listed, pick the generic 3,200 ppm or type your own target. The cell you choose is remembered on this device for the next visit.
Hayward, Pentair and Intex
Choose the system in the list and the target fills itself. For Hayward the manual also says the cell's Check Salt light comes on below 2,700 ppm and the High Salt light shuts the unit down, and it wants plain salt that is at least 99% sodium chloride with no iodine and no anti-caking additive. Intex's saltwater system works at 3,000 ppm and prints a table by pool model. Its manual's rule of thumb is 0.025 lb per gallon to start up, so a 4,760 gallon pool needs about 119 lb.
Pool salt chart by size, and a PDF
The chart below the calculator lists pounds of salt for eleven pool sizes from 5,000 to 50,000 gallons and seven starting levels, at the target above. A 5,000 gallon pool from 0 needs 134 lb, 15,000 gal needs 401 lb, and 30,000 gal needs 801 lb. Use the print button and choose "Save as PDF" in the print window for a file, or print it for the pump shed. It changes with the system you pick, so a Pentair chart at 3,400 ppm is different from a Hayward chart at 3,200 ppm.
Too much salt
Salt does not leave the pool with time, chlorine or filtering. Only replacing water lowers it. Enter a level above your target and the calculator switches to a drain percentage: (current − target) ÷ (current − fill water level). From 4,000 ppm to 3,200 ppm with fill water near 0 ppm, that is 20%, or 3,000 gallons of 15,000. If your tap water carries 200 ppm the share rises to about 21%. Drain and refill in stages and retest, because a second small round beats an over-shoot. The same draining also removes stabilizer and calcium, so recheck the pool stabilizer level afterwards.
Above-ground pools and litres
Above-ground pools hold less than the box says: use the water at your fill line from the pool gallons calculator. Switch the header toggle to metric for litres and kilograms; the maths stays in litres of water and the answer shows kilograms, with the 40 lb bag equal to 18.1 kg.
What to check after adding salt
Run the pump for 24 hours with the salt brushed off the floor, then test. Keep chlorine in range while the cell is offline, and watch free chlorine and cyanuric acid together, because Hayward asks 60 to 80 ppm CYA but Pentair and CircuPool ask 30 to 50 ppm. We follow the manual of the cell you select, and warn above 90 ppm, the CDC limit. For a full test-strip plan use the pool chemical calculator, and see every tool in pool chemistry.