Not sure? Use the volume calculator.
To raise salt by 800 ppm, add
80 lbs
≈ 2.0 forty-pound bags
The math (it's exact)
Unlike chlorine dosing, salt math has no product-strength fudge factors: salt is salt. One ppm is one pound per million pounds of water, and water weighs 8.34 lbs per gallon, so:
Pounds of salt = gallons × 8.34 × (target ppm − current ppm) ÷ 1,000,000
A 12,000-gallon pool going from 2,400 to 3,200 ppm needs about 80 lbs — two 40-lb bags.
Check the cell's sticker, not folklore. Most residential salt systems want 2,700–3,400 ppm, but ranges differ by manufacturer. Aim for the middle of your cell's range, and trust a calibrated meter or drop test over the salt system's own display — drifting salt readings are one of the most common false alarms in salt-pool service.
Adding salt the right way
- Use pool-grade salt (99%+ pure, no additives — never rock salt or iodized).
- Pour into the shallow end with the pump running and brush it around; it dissolves in a few hours.
- Run the pump 24 hours before trusting a new reading, and keep the chlorinator off until the salt has dissolved.
- Went over? There's no chemical that removes salt — partial drain and refill is the only fix, which is why this calculation is worth doing on paper first.
On a route, salt level is a once-a-month check, not a weekly one — but it belongs in the pool's service history with everything else. Tadpole keeps readings per stop, so the trend is there when the cell starts complaining.
