What a salt water pool system actually is
The names are confusing. Salt water pool system, pool salt system, salt chlorinator, saltwater generator, salt chlorine generator: all of them describe the same equipment. It has one purpose, which is to make chlorine from salt that is already dissolved in the pool.
It does not replace the pump or the filter. It is added to them. If you want the chemistry, see how salt water pools work. This page is about the hardware.
The components
- Salt cell
- A housing plumbed into the return line, holding a stack of coated titanium plates. Chlorine is produced here. It is the consumable part of the system.
- Control unit
- The power supply and brain. It sets output, reads salt level and water temperature, and reports faults such as low salt or a scaled cell.
- Flow sensor
- Stops the cell from running when water is not moving through it.
- Optional automation
- Ties the salt system to the pump, heater, lights and a phone app, and on some setups adds automatic pH control.
Where it goes on the equipment pad
Order matters. Water should pass through the pump, then the filter, then the heater, and only then the salt cell, immediately before it returns to the pool.
The reason is simple. Chlorine is at its most concentrated right as it leaves the cell. Placing the cell last keeps that concentrated water away from the heater and other equipment.
How to size a salt system for an inground pool
Manufacturers rate each model by the maximum pool volume it can serve, in gallons. Treat that figure as a ceiling under ideal conditions, not a target.
| Factor | Effect on sizing |
|---|---|
| Pool volume | The starting point. Choose a rating comfortably above it. |
| Sun exposure and altitude | Strong ultraviolet light destroys chlorine faster. Size up. |
| Water temperature | Warm water uses more chlorine. Heated pools and attached hot tubs need more capacity. |
| Bather load | A pool that hosts crowds needs more than one used by two people. |
| Pump run time | The cell only works while water flows. Short run times need a larger cell. |
| Shallow or beach areas | Large shallows warm up and consume chlorine quickly. Common in lagoons. |
A system rated well above the pool's volume can run at a lower output setting. That means less wear on the plates, a longer cell life and capacity in reserve for a hot week in July.
Features worth having
- Reverse polarity. The control unit switches the current direction periodically, which helps shed scale from the plates.
- A clear salt readout. A number is more useful than a single warning light.
- Boost mode. Runs the cell at full output for a set period after heavy use or a storm.
- Cold-water cutoff. Protects the cell by stopping production when the water is too cold.
- A cell that is easy to remove. Unions on both ends make inspection and cleaning a five-minute job.
How long it lasts and what wears out
The control unit can last many years. The cell is the wear part. Each hour of operation uses a little of the coating on the plates, and when it is gone the cell stops producing and is replaced.
Three things shorten a cell's life: running it at high output constantly, letting calcium scale build up on the plates, and cleaning it with acid too often or too aggressively. Good water balance is the cheapest way to protect it. The routine is in our maintenance guide.
Salt systems and climate
Sun, salt air and cold all matter.
In strong sun, whether at altitude or in the far south, chlorine is destroyed faster, so stabilizer levels and system size carry more weight. On the coast, the equipment pad itself should be specified for salt air.
Cold stops production. Most cells shut down somewhere below 50 to 60 degrees Fahrenheit. When the pool is closed for winter, the cell should be drained and protected from freezing in line with the manufacturer's instructions, and many owners simply remove it and store it indoors.
New build or existing pool?
- If you are building new
- Decide on salt before the design is finished, so stone, metal and equipment are all chosen to suit.
- If you have an existing chlorine pool in good condition
- A salt system can usually be added. Have the heater, fittings and coping checked first.
- If the pool has soft stone or older metalwork
- Weigh the cost of protecting or replacing it against the benefit. Our comparison may help.
For a new salt water pool, the system is specified as part of the whole equipment package, alongside the pump, filter, heater and cover.
