How to clean a salt cell
Open and look at your salt cell about every 3 months, but clean it only if you see white, crusty scale on the plates. Try a garden hose first. If scale remains, soak the plates in 1 quart of muriatic acid added to 1 gallon of water (the mix both Hayward and Pentair specify) until the fizzing stops, for no longer than 30 minutes.
Always follow your product’s label directions. Pool and spa chlorine, bromine, shock and algaecides are EPA-registered pesticides: use products labeled for pool or spa use, and don’t swim or soak until levels are within the limit on your product’s label. If this page and a label disagree, the label wins.
On this page (8 sections)
Signs it needs cleaning
A salt cell is a stack of coated metal plates inside a clear or gray housing in the return line. Scale is calcium carbonate that forms on those plates, and it cuts chlorine output. Look for:
- An "Inspect Cell" light. On the Hayward AquaRite it flashes after about 500 hours of operation as a reminder, and stays on when efficiency is badly reduced.
- White or light-colored crusty, flaky deposits bridging the gaps between plates when you look through the cell.
- Chlorine falling at the same output setting, with salt, pump hours, and stabilizer (CYA) unchanged.
- Debris such as leaves or hair caught between plates, which some filters let through.
If the plates look clean, do not acid wash. Pentair warns that excessive acid washing damages the blades, and it only recommends acid when vigorous foaming shows there is scale to dissolve.
Safety first: acid into water
Safety
- Turn off power to the chlorinator (and the pump) before removing the cell.
- Wear rubber gloves and eye protection. Work outdoors or in a well-ventilated area.
- Use a clean plastic bucket. Always add acid to water, never water to acid. Pouring water into acid can make it spatter.
- Never let acid touch chlorine, chlorine tablets, or a bucket that held them. Together they release chlorine gas.
- Keep the cord and wire compartment out of the solution.
- If acid gets on skin or in eyes, rinse with plenty of water. For exposure or swallowing, call Poison Control at 1-800-222-1222.
Always follow the label on your acid. More in the pool chemical safety guide.
Step by step
- Turn off the chlorinator and pump, close valves if the cell sits below water level, and unscrew the cell unions. Pentair cells disconnect from the power center.
- Look through the cell. If you see no deposits, reinstall it and stop here.
- Flush with a high-pressure garden hose from both ends. Pentair notes that much of the buildup is slushy and blows out. Hayward allows a plastic or wooden tool for stubborn bits. Never use metal, which scratches the plate coating.
- If scale remains, pour 1 gallon of water into a plastic bucket, then slowly add 1 quart of muriatic acid. That is a 4:1 mix, about 6% hydrochloric acid if your jug is 31.45%.
- Stand the cell upright and fill it (or submerge it) so the solution just covers the plates without reaching the wiring. Pentair sells a cap kit that holds acid inside the cell.
- Let it fizz. Foaming is scale dissolving. Hayward says a few minutes. Pentair says until the foaming stops, but never more than 30 minutes.
- Rinse inside and out with clean water and look again. Repeat the soak only if deposits are still visible.
- Reinstall the cell, restore power, and reset the inspection reminder (Hayward: hold the diagnostic button for 3 seconds).
- Dispose of the used acid according to local rules, and do not reuse the bucket for chlorine.
How often
Inspecting and cleaning are two different schedules:
- Inspect: every 3 months or after cleaning your filter (Hayward). Pentair suggests every 2 months if your cell tends to scale, and more often in hard-water areas.
- Clean: only when you see scale. Many cells go a season without an acid wash because they reverse polarity every few hours to shed light deposits. Pentair's reverse cycle runs 2 hours for the first 192 hours, then 3 hours. It can be lengthened to 5 hours to extend blade life.
If you are acid washing every month, the problem is the water, not the cell.
Prevent scale (LSI, pH)
Hayward's manual says buildup on the cell points to unusually high calcium in the pool. The broader rule is water balance, measured by the Langelier Saturation Index (LSI). Above zero, the water tends to deposit scale. Below zero, it tends to dissolve plaster and metal. pH has the biggest day-to-day effect, and pH in salt pools tends to drift up. Here is how LSI moves with pH alone, at 85 °F, calcium hardness (CH) 300, total alkalinity (TA) 80, and CYA 70:
| pH | LSI | Zone |
|---|---|---|
| 7.2 | −0.44 | corrosive |
| 7.4 | −0.26 | balanced |
| 7.6 | −0.07 | balanced |
| 7.8 | +0.12 | balanced |
| 8.0 | +0.31 | slightly scaling |
Computed with our LSI model (cyanurate-corrected alkalinity). Same pool at pH 7.8 with CH 500 and TA 120: +0.57, scaling.
Keeping pH at 7.4–7.6 and calcium in range does more for the cell than any cleaner. Run your own numbers in the LSI calculator, and see salt pool care for why pH keeps rising.
Cell errors that aren't scale
- Low salt. Cells slow down or stop when salt is below their range. Check your level with the salt level guide.
- Cold water. The AquaRite stops below 50 °F and the IntelliChlor below about 52 °F. That is normal, not a fault.
- No flow. A dirty filter, a closed valve, or air in the line trips the flow switch.
- Worn plates. Hayward says an "Inspect Cell" light that stays on after a thorough cleaning may mean the cell needs replacing. Pentair designs its cell for about 10,000 hours, roughly five years of average use, and shows hours used in its status mode.
- Chlorine demand. Something in the water can use up chlorine as fast as the cell makes it (Pentair lists phosphates and nitrates as common suspects). Phosphate itself doesn’t use up chlorine, but algae that feed on it do, so check for early algae first; see pool phosphates. The cell works, but the water uses up the chlorine.
Still stuck? Check the other pool water problems, or call the manufacturer before replacing an expensive cell.
FAQ
What is a salt cell?
The part of a salt water chlorinator that makes chlorine: a housing in the return plumbing with coated metal plates inside. A control box sends low-voltage power to the plates. The cell is a wear part and eventually needs replacing.
How does a salt cell work?
By electrolysis. As salty water flows between the charged plates, chloride is turned into chlorine, which dissolves at once into hypochlorous acid and hypochlorite, the same sanitizer liquid chlorine makes. After it reacts, it returns to salt, so the salt is reused.
How often should I clean my salt cell?
Inspect it about every 3 months (every 2 months if it tends to scale) and clean it only when you see scale. Unnecessary acid washing shortens the life of the plates.
Sources
- Hayward, AquaRite manual, sections "Maintaining the Aqua Rite System" and "Servicing and Cleaning": PDF
- Pentair, IntelliChlor SCG Installation and User's Guide, P/N 520589 Rev. R (2023), "Cleaning the IntelliChlor SCG Cell Blades": PDF
- Pentair, IntelliChlor Quick Start Guide and Tips (reverse cycle hours): PDF