Salt water pool calculator
A salt chlorinator makes chlorine by electrolysis of dissolved salt. The salt is not consumed, only lost to splash-out and backwashing.
ppm
ppm
Salt to add
40.00kg
- Bags needed
- 2
- Salinity increase
- 1000 ppm
- Salinity after adding fresh water
- 2200 ppm
- Salt needed after that dilution
- 40.00
- Salt already in the pool
- 88.0
- Salt in the pool afterwards
- 128.0
- Salinity compared with seawater
- 9.14 %
Show the working
- Pool volume = 40 000
- Current salinity = 2200
- Target salinity = 3200
- Salt bag size = 25
- Fresh water to be added = 0
- Salinity increase = max(3200 - 2200, 0) = 1000
- Salt to add = 40 000 * 1000 / 1e6 = 40
- Bags needed = 25 > 0 ? ceil(40 / 25) : 0 = 2
- Salinity after adding fresh water = (40 000 + 0) > 0 ? 2200 * 40 000 / (40 000 + 0) : 0 = 2200
- Salt needed after that dilution = max(3200 - 2200, 0) * (40 000 + 0) / 1e6 = 40
- Salt already in the pool = 40 000 * 2200 / 1e6 = 88
- Salt in the pool afterwards = 88 + 40 = 128
- Salinity compared with seawater = 3200 / 35000 * 100 = 9.142 86
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- salt in kg = volume in litres x ppm increase / 1 000 000
A salt pool at 3200 ppm is about a tenth as salty as seawater, which is why you can barely taste it.
Salt is only lost through water loss. Evaporation leaves it behind and concentrates it.