Your salt pool is turning green, the chlorinator shows a salt or cell warning, or the chlorine test reads zero while the system says it is working. Most salt water pool problems trace back to the salt level, a scaled cell, cold water, low stabilizer or a pump that does not run long enough. This page explains how a salt chlorinator works, which parts fail, the makers’ numbers, and when to call a pro.
How does a salt water chlorinator work?
A salt pool is still a chlorine pool. The chlorinator makes the chlorine from salt in the water, so the usual chlorine and pH rules apply.
- Salt dissolves in the pool. Hayward aims for about 3,200 ppm (parts per million) of salt, enough for the cell but low enough that most people cannot taste it.
- Water flows through the cell. The cell is a tube of coated metal plates in your return line. A flow switch or sensor stops the cell if no water is moving.
- The cell makes chlorine. Electric current across the plates turns salt into chlorine. Pentair explains that the chlorine kills germs and algae, then turns back into salt to be used again.
- The control sets the output. On a Hayward AquaRite, 50% output means the cell makes chlorine for half the time the pump runs. No pump, no chlorine.
- The cell cleans itself. Hayward, Pentair and Jandy cells reverse polarity on a timer to shed scale, the white crust that calcium leaves on the plates.
- Sensors shut it down. Low salt, high salt, cold water or no flow will slow or stop chlorine production.
The process also makes sodium hydroxide, which Taylor says pushes pH up, so salt pools need acid more often.
Which salt system parts fail, and what are the signs?
| Part | What it does | Sign it is failing |
|---|---|---|
| Salt cell | Turns salt into chlorine | Low chlorine even at high output; cell warning stays on after a cleaning |
| Cell plates (scale) | Carry the current | White crust between plates; low salt reading when the pool has plenty |
| Flow switch or sensor | Proves water is moving | No Flow light while the pump runs |
| Salt sensor | Reads salinity | Reading more than 500 ppm off from your own salt test |
| Temperature sensor | Stops the cell in cold water | Cold water warning when the water is warm |
| Control board or power center | Powers the cell and runs the display | Blank display, board error code, blown fuse |
What should I check first when my salt pool has low chlorine?
- Your own test. Test free chlorine and salt with your own kit or meter. Do not rely on the control’s display alone. Hayward says the system should read within 500 ppm of an independent salt test.
- Pump run time and output. Hayward lists a short filter time, under 8 hours for an average pool, as a cause of little or no chlorine. Raise output in steps and retest after 24 hours. If the pump is the problem, see our pool pump problems hub.
- Stabilizer. Low CYA is on Hayward’s list of causes too. Hayward, Pentair and Jandy all call for 30 to 50 ppm outdoors.
- Water temperature. All three big brands stop or slow the cell in cold water, so early and late in the season you may need to add chlorine by hand.
- The cell itself. Turn off power, remove the cell and look through it toward a light. Scale or debris between the plates cuts output.
- Chlorine eaters. Pentair says nitrates above 10 ppm and phosphates above 125 ppb (parts per billion) can drain chlorine, and metals can damage the cell.
Safety first. Turn off power to the chlorinator at the breaker before you remove the cell. When you acid wash, wear goggles and rubber gloves, work in a well-ventilated spot outdoors, and always add acid to water, never water to acid. Keep the cell’s wire end out of the acid. Never mix acid with chlorine or other pool chemicals, and keep kids and pets away from the bucket. If a breaker or GFCI (ground fault circuit interrupter, the safety outlet or breaker that cuts power on a shock risk) keeps tripping, stop and call an electrician.
Salt water pool numbers to know
These numbers come from each maker’s owner’s manual or service guide for one product line. Your model may differ, so check its label and manual.
| Spec | Hayward AquaRite | Pentair IntelliChlor | Jandy TruClear |
|---|---|---|---|
| Salt target | 2,700 to 3,400 ppm, 3,200 best | 3,600 ppm recommended; light shows “good” from 2,800 to 4,500 | 3,000 ppm recommended |
| Low salt | Warning at 2,400 to 2,700; stops at 2,300 or less | Reduced output below 2,800; off below 2,600 | Below 2,500 causes early cell failure |
| Cold water | Output cut back at 60°F; stops at 50°F | Off below 52°F, plus or minus 3°F | Running below 55°F not recommended |
| Cell check | Inspect every 3 months; reminder light at 500 hours | Every 2 months if the cell tends to scale | Once a month |
| Acid wash mix | 4 parts water to 1 part muriatic acid | 1 quart muriatic acid in 1 gallon of water | 1 part muriatic acid to 10 parts water; 30 minutes max |
| Cell life | See your model’s manual | About 10,000 hours, roughly 5 years | See your model’s manual |
| Stabilizer (CYA) | 30 to 50 ppm outdoors | 30 to 50 ppm | 30 to 50 ppm |
Hayward vs Pentair vs Jandy: how are salt systems different?
All three work the same way, but the details change how you troubleshoot. The biggest one is the salt target. A reading of 3,600 ppm is right on target for an IntelliChlor, yet it is above the range in Hayward’s AquaRite manual, so never copy a friend’s number. Use the one printed for your system.
The warning lights differ too. The AquaRite flashes Check Salt and Inspect Cell lights, and after a cleaning you press the Diagnostic button to reset the reminder. The IntelliChlor has an hours meter that shows how close the cell is to its rated life.
When you buy parts, cells and controls are not swapped between brands, and often not between models of one brand. Write down the model number from the cell and control label before you order. Cells are also sized by pool volume; Hayward’s AquaRite cells, for example, are rated for pools up to 15,000, 25,000 or 40,000 gallons.
When should you call a pool or spa pro?
- A clean cell still makes little chlorine. Hayward says that if the Inspect Cell light stays on after a thorough cleaning, the cell may be worn and need replacing.
- Board or power errors. A circuit board fault code, a blown fuse or a blank display needs a tech with a meter.
- Salt far too high. The only way down is to drain part of the water and refill, and draining can damage some pools.
- Still green after shocking. If manual shocking will not clear it, a full water test helps; see our green and cloudy pool water hub.
Pool pros bill by the visit or by the hour, so have your test results and model numbers ready.
Common questions
Why does my salt water pool go green?
It goes green for the same reason any pool does: not enough free chlorine. In a salt pool that usually means low salt, a scaled cell, cold water, short pump runs, low stabilizer or high phosphates. Shock with liquid chlorine or use the system’s boost mode, then find and fix the cause; our pool chemistry hub covers the balance side.
How do you know if your salt cell is bad?
Rule out the easy causes first: correct salt, clean plates, CYA in range, warm water and enough pump time. If chlorine still stays low with the output turned up, the cell is likely worn. On an AquaRite, an Inspect Cell light that stays on after a good cleaning points the same way.
How long does a salt cell last?
Pentair rates its IntelliChlor cells at about 10,000 hours, roughly five years of average use. Hayward and Jandy do not give a life figure in the manuals we used. Jandy warns that low salt, cold water and too much acid washing all shorten cell life.
How often should you clean a salt cell?
Inspect it often and clean it only when you see scale. Hayward says to inspect every 3 months, Pentair every 2 months if the cell tends to scale, and Jandy monthly. Hayward notes that most cells need cleaning 3 to 4 times a year when pH stays between 7.2 and 7.8 and calcium is moderate.
How much salt does a 10,000 gallon pool need?
Hayward’s chart calls for about 267 pounds to bring 10,000 gallons from zero salt to 3,200 ppm, which is seven 40 pound bags. Most pools already hold some salt, so test first and add less. Brush it in and let the pump run 24 hours before you test again.
Is 4,000 ppm salt too high for a pool?
It depends on your system. It is above Hayward’s 3,400 ppm limit and can trigger a High Salt shutdown, and Hayward says salt starts to taste at about 3,500 to 4,000 ppm. Pentair’s IntelliChlor reads it as good, while Jandy’s TruClear manual targets 3,000 ppm.
How much does it cost to replace a salt cell?
Prices vary by brand, cell size and model, so we do not quote one. Get the exact model number from your cell and control, and rule out scale and low salt before you buy.