How Much Salt Do I Need for a Saltwater Pool? Pounds and Bags
Part of the project planner: Planning pools, ponds and water storage.
A 15,000 gallon pool needs about 400 pounds of salt (11 bags of 40 lb) to go from fresh water to the usual 3,200 ppm. If the water already has 400 ppm of salt, the figure is 350 pounds. The tables below cover other pool sizes and levels.
Salt by pool size
To reach 3,200 ppm from fresh water, and from 400 ppm, in pounds and 40 lb bags:
| Pool volume | From 0 ppm | From 400 ppm |
|---|---|---|
| 10,000 gallons | 267 lb (7 bags) | 234 lb (6 bags) |
| 12,000 gallons | 320 lb (9 bags) | 280 lb (8 bags) |
| 15,000 gallons | 400 lb (11 bags) | 350 lb (9 bags) |
| 20,000 gallons | 534 lb (14 bags) | 467 lb (12 bags) |
| 25,000 gallons | 667 lb (17 bags) | 584 lb (15 bags) |
| 30,000 gallons | 801 lb (21 bags) | 701 lb (18 bags) |
How the target level changes it
For a 15,000 gallon pool starting from fresh water:
| Target | Salt needed | 40 lb bags |
|---|---|---|
| 2,700 ppm | 338 lb | 9 |
| 3,000 ppm | 375 lb | 10 |
| 3,200 ppm | 400 lb | 11 |
| 3,400 ppm | 425 lb | 11 |
| 4,000 ppm | 500 lb | 13 |
How the starting level changes it
For a 15,000 gallon pool going to 3,200 ppm:
| Salt now | Salt to add | 40 lb bags |
|---|---|---|
| 0 ppm | 400 lb | 11 |
| 400 ppm | 350 lb | 9 |
| 1,000 ppm | 275 lb | 7 |
| 2,000 ppm | 150 lb | 4 |
| 3,000 ppm | 25 lb | 1 |
Put your own gallons and levels into the pool salt calculator. If you do not know the volume, use the pool volume calculator.
The formula
Salt level is in parts per million (ppm), and a gallon of water weighs 8.34 pounds, so:
Every 1,000 ppm in a 15,000 gallon pool is 125 pounds of salt.
How to add it
- Test the salt level first with a reliable kit, and balance the pH and chlorine as normal.
- Turn the pump on. Pour the salt into the shallow end, or around the edge, and brush it to help it dissolve.
- Run the pump for 24 hours to mix it evenly, then retest. Add more in small amounts if the reading is low.
- Do not run the salt chlorine generator until the reading has settled in the range its manual calls for.
Too much salt?
Salt does not evaporate or break down, and you cannot filter it out. The only way to lower the level is to drain some of the water and refill with fresh water. Draining a share of the pool lowers the level by about that share:
| Water drained and replaced | From 4,000 ppm | From 3,600 ppm |
|---|---|---|
| 10% | 3,600 ppm | 3,240 ppm |
| 20% | 3,200 ppm | 2,880 ppm |
| 30% | 2,800 ppm | 2,520 ppm |
| 50% | 2,000 ppm | 1,800 ppm |
Mistakes that cost people money
- Adding the salt in one go without knowing the true volume of the pool. Add about 80% first, and test.
- Using salt that is not pool-grade, which can contain additives that stain the pool or clog the cell.
- Running the pump too little for the salt to dissolve, so it sits on the floor and stains the finish.
- Forgetting that the salt level drops as water is lost to splash-out, backwashing and rain.
Frequently asked questions
How much salt do I need for a 15,000 gallon pool?
About 400 pounds (11 bags of 40 lb) to go from fresh water to 3,200 ppm. If the pool already has 400 ppm, about 350 pounds (9 bags).
How much salt do I need for a 20,000 gallon pool?
About 534 pounds from 0 ppm to 3,200 ppm, which is 14 bags of 40 lb.
What should the salt level be in a saltwater pool?
Most salt chlorine generators want 2,700 to 3,400 ppm, with 3,200 ppm typical. Check your cell's manual.
How do I lower the salt level in a pool?
You cannot remove salt. Drain some of the water and refill with fresh water. Draining 10% lowers the level by about 10%.
More guides
Tools & materials for this project
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Estimates only. Quantities depend on your materials, site and supplier. Confirm important numbers before you order, and follow local building codes for anything structural.