Inspect and clean the salt cell before closing (acid-wash only if calcium scale is visible), confirm salt level is in the 2,700-3,400 ppm range most cells require (check your specific manufacturer’s target), then either remove the cell and store it indoors in freezing climates or leave it in place with the control box powered down, per your pool equipment manufacturer’s cold-weather guidance. Never run a salt cell in water below approximately 50degF; most cells stop generating chlorine effectively below that temperature, and continuing to run them can shorten cell life.
How do you winterize a salt chlorinator?
Inspect and clean the salt cell before closing your pool (acid-wash only if calcium scale is visible), confirm salt level is in the 2,700-3,400 ppm range most cells require (check your specific manufacturer’s target), then either remove the cell and store it indoors in freezing climates or leave it in place with the control box powered down, per your manufacturer’s cold-weather guidance. Never run a salt cell in water below approximately 50degF; most cells stop generating chlorine effectively below that temperature and continuing to run them can shorten cell life.
Salt systems get a reputation for being low-maintenance, and during the swim season that’s fair. But the cell itself is a wear item, and how you treat it going into winter has more effect on whether you’re buying a $200-700 replacement cell next season than almost anything you do the rest of the year.
Step 1: Inspect the Cell Before Closing
Remove the cell from its housing (most twist-lock cells can be removed without tools) and look at the metal plates inside. Light scale buildup is normal and expected. Heavy white or gray calcium scale between the plates restricts water flow and reduces chlorine output, and it needs to be addressed before winter storage, not left to sit for months.
How to Acid-Wash a Scaled Cell
If scale is visible: mix a solution per your cell manufacturer’s instructions, typically a 4:1 water-to-muriatic-acid ratio, in a plastic (not metal) container. Submerge the cell’s plate end only, not the cord or connector end, for the time specified in your manual (often 1-15 minutes, checked periodically). Bubbling indicates the acid is dissolving scale. Remove once bubbling stops or scale visibly clears, then rinse thoroughly with fresh water before reinstalling or storing. Try this salt cell cleaner.
⚠ WARNING: Always add acid to water, never water to acid, and always wear eye protection and gloves. Acid-washing should be done outdoors or in a well-ventilated area, and never in a metal container, as the acid will react with it.
Step 2: Confirm Salt Level Before Closing
Test salt level before closing so you know where you stand for spring startup. Most cells target 2,700-3,400 ppm, though this varies by manufacturer; check your specific unit’s target range. Salt does not evaporate or get “used up” the way chlorine does; a properly closed pool should have roughly the same salt level in spring, minus any dilution from rain and snowmelt that get into the water over winter.
| Salt Level | Status | Action Before Closing |
| Below 2,700 ppm | Low | Add salt now, before closing, so it has time to fully dissolve |
| 2,700-3,400 ppm | Normal (verify against your model) | No action needed |
| Above 3,400 ppm | High | Note the level; do not add more salt. Dilution may be needed at opening |
Step 3: Decide Whether to Remove the Cell for Winter
Climates with hard freezes: Remove the cell and control box components rated for indoor storage, and store them indoors. A cell left in a drained or freezing system risks internal cracking if any residual water freezes inside it.
Mild climates with no hard freeze: Many manufacturers allow the cell to stay in place through a mild winter, with the control box simply powered off. Check your specific model’s cold-weather guidance since this varies by brand and cell design.
All climates: Power down and unplug the control box itself for the winter regardless of whether the cell is removed. This protects the electronics from power surges and prevents anyone from accidentally powering on a system with the water level too low for the cell (running a cell without adequate water flow can damage it in seconds).
✓ KEY FACT: Do not run your salt chlorinator once water temperature drops below approximately 50degF. Salt cells become significantly less efficient at generating chlorine in cold water, and continuing to run the cell at cold temperatures accelerates plate wear without producing meaningful chlorine output. This is a good natural cutoff point for when to complete the winterizing steps above.
What Winter Does to an Unmaintained Cell
A cell closed with heavy scale buildup and left untouched all winter will have that scale bond more firmly to the plates over months of sitting, making the spring acid-wash far more difficult and sometimes impossible to fully clear, shortening the cell’s remaining life. A cell that freezes with water inside it can crack internally in a way that isn’t visible until it fails to generate chlorine the following season, well after any warranty return window on a visible defect has closed.
Pool Owners Salt Cell Maintenance FAQ
My cell has heavy scale I can’t remove even with an extended acid bath. Heavily scaled cells beyond a certain point don’t fully recover function even after cleaning, since the plate coating itself can degrade under prolonged heavy scale contact. If a full acid wash per manufacturer instructions doesn’t restore visible clean plates, budget for a replacement cell rather than closing the pool with a marginal one.
I forgot to remove my cell before a hard freeze hit. Inspect it as soon as you can safely access it. Look for hairline cracks in the housing, and don’t power it on until you’ve confirmed there’s no visible damage. If in doubt, have it tested by a pool professional before running it in spring; a cracked cell can leak or fail to generate chlorine, and running a damaged unit can be a safety issue.
My salt level tested high at closing. High salt doesn’t harm the cell the way low salt (which causes the cell to work harder and wear faster trying to compensate) does, but very high salt can affect metal fittings and ladders over time and will need partial dilution at spring opening. Note the reading now so you’re not guessing in spring.
Where to Buy
Doheny’s carries replacement salt cells across major system brands, pool test kits for salt level, and acid-wash supplies, with free shipping on orders over $50. Shop Doheny’s salt system parts →
Related Guides
-> Pool Closing and Winterizing Guide: The Complete Step-by-Step Process