Saltwater Pool Guide — How Much Salt to Add

Get the salinity right the first time—because the only way to lower salinity is to drain water.

A saltwater pool is essentially still a chlorine pool; the difference lies in the source of the chlorine. A salt chlorine generator (SWG) continuously converts dissolved salt into chlorine via an electrolytic cell. This process works effectively only when the salinity falls within the equipment's design range, which is why salt calculators base their calculations on current versus target ppm readings.

How salt turns into chlorine

The salt chlorine generator's electrolytic cell electrolyzes sodium chloride into chlorine gas; this gas dissolves instantly, providing sanitizing effects identical to any other chlorine source. Salt itself is not consumed in the long run—most of it reverts to salt after the chlorine does its job—so salinity remains constant unless water physically leaves the pool. Water splashing out, filter backwashing, leaks, and dilution from heavy rain are the actual causes of salinity drops, not evaporation; evaporation removes only the water, leaving the salt behind.

Calculation formulas used

The dosage formula is: Pounds of salt = (Target ppm − Current ppm) × (Pool volume in gallons ÷ 10,000) × 0.0834. The final coefficient implies that raising salinity by 1,000 ppm requires approximately 8.34 pounds of salt per 1,000 gallons—which makes sense, given that a gallon of water weighs about 8.34 pounds and ppm is a weight-based ratio. Example calculation: A 15,000-gallon pool reads 2,600 ppm and has a target of 3,200 ppm (requiring a 600 ppm increase); thus, 600 × 1.5 × 0.0834 ≈ 75 pounds of salt. Why the default target is 3,200 ppm

The calculator defaults to a target of 3,200 ppm and displays an ideal range of 2,700–3,400 ppm. The lower limit is critical: standard residential electrolytic cells require a minimum of 2,700 ppm; below this threshold, many units will reduce output or stop chlorine production entirely. Setting the target in the middle of the range provides a buffer, ensuring that normal dilution from rainfall or backwashing does not immediately trigger a "low salt" error.

Adding salt—and what to do if you add too much

With the pump running, spread the salt evenly across the shallow end and allow the circulating water to fully dissolve it before re-testing; high-purity evaporated salt dissolves cleanly, whereas rock salt or water softener pellets may contain additives. Please note that the calculator only provides a dosage recommendation if the target level is higher than the current reading. No chemical can remove salt—if too much is added, the only remedy is to partially drain the pool and refill it with fresh water, which highlights the importance of accurately measuring pool volume before dosing.