Pool Salt Calculator

A 10,000 gallon pool starting from zero needs about 267 pounds, which is seven 40 pound bags, to reach 3,200 ppm. A 20,000 gallon pool needs about 534 pounds, or fourteen bags. If the pool already has salt in it, you only need to make up the gap. Enter your reading above.

Most salt chlorine generators are designed for 3,200 ppm, with a working range of 2,700 to 3,400 ppm. Below about 2,700 the cell stops producing chlorine properly and may show a low salt warning. Above 3,400 you gain nothing, and past 6,000 the water starts to taste salty and corrode fittings.

You can usually swim once the salt has dissolved, which takes about 20 minutes of brushing with the pump running. Wait 24 hours before you trust a salt reading, because undissolved salt sitting on the floor has not reached the cell yet and the meter will read low.

Use pool grade sodium chloride, at least 99.8 percent pure, sold as pool salt or solar salt. Do not use rock salt, table salt with iodine, or water softener salt with additives. The additives stain the surface and cloud the water. Pool salt costs a few dollars more a bag and dissolves faster.

Salt leaves only with water. Splash out, backwashing, draining, leaks and heavy rain overflow all carry salt away. Evaporation does not: the water goes and the salt stays, so evaporation actually raises the reading. A level that keeps falling with no obvious cause usually means a leak worth investigating.

Yes. Past about 3,600 ppm the generator gains nothing, and high levels corrode ladders, rails, heaters and stone coping over time. The only fix is dilution: drain part of the water and refill. That is why it is better to add three quarters of what you think you need and test again.

Drain some water and replace it with fresh. The share to replace is the excess divided by the current reading. A pool at 4,000 ppm aiming for 3,200 needs about 20 percent of its water swapped. There is no chemical that removes salt, and it will not evaporate away.

Most pools need topping up two or three times a year, usually after heavy rain, a backwash or a partial drain. Test monthly during swim season. A saltwater pool that is not losing water should hold its level for months, so frequent additions point at a leak or heavy splash out.

A saltwater pool is a chlorine pool. The generator makes chlorine from the salt as water passes through the cell, so you are not buying and pouring it. You still test free chlorine, still balance pH and alkalinity, and still shock the pool after heavy use or a storm.

Starting from zero, about 400 pounds, which is ten 40 pound bags, to reach 3,200 ppm. Coming up from 2,700 ppm it takes about 63 pounds, so two bags. The gap between your reading and your target matters far more than the size of the pool on its own.