Saltwater pool owners add too little salt (cell burns out) or too much (corrosion on equipment and scale on surfaces). Here's the right math.
Target salinity
Check your specific salt cell's manufacturer target. Common ones:
| Salt system | Target ppm |
|---|---|
| Pentair IntelliChlor | 3,200–3,500 |
| Hayward AquaRite / T-Cell | 3,200 |
| Jandy AquaPure | 3,000–3,500 |
| CircuPool RJ-Series | 3,200–4,000 |
Dosing formula
To raise salinity by 500 ppm in a 20,000-gallon pool, you need about 85 lbs of pool salt.
General formula: (target ppm − current ppm) × gallons ÷ 120,000 = lbs of salt.
Example: going from 2,500 to 3,200 ppm in a 15,000 gallon pool:
(3,200 − 2,500) × 15,000 ÷ 120,000 = 87.5 lbs of salt (round up to 90 lbs, or two 50-lb bags).
How to add it
- Brush the pool to keep salt from piling on the floor.
- Broadcast salt directly into the pool (not the skimmer — it'll pack into the filter).
- Run pump 24 hours to dissolve.
- Retest after 24 hours — cells read accurately once salt fully dissolves.
If salt is too high
Only fix is partial water exchange — drain some, refill with fresh water. No chemical lowers salinity.
Only use real pool salt
Never use water-softener salt, rock salt, or iodized salt. Get 99.8%+ pure sodium chloride pool salt. Impurities stain pools and kill salt cells.
Part of our saltwater pool maintenance series.
Frequently Asked Questions
Only 99.8%+ pure sodium chloride pool salt. Never water-softener salt, rock salt, or iodized salt — impurities stain pools and destroy salt cells.
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