How to Tell if Your Salt Cell Needs Replacing

Written by Michael Dean
October 3, 2023

replacing the salt cell in a pool

Saltwater pools continue to grow in popularity in no small part due to their minimal maintenance needs. However, minimal maintenance doesn’t mean no maintenance at all. One key element of keeping your saltwater system properly working is monitoring your Salt Chlorine Generator (SCG) cell.

Ideally, a salt cell will last for about five years, but problems can occur, and issues aren’t always easy to spot. Here’s how to check salt cell function, replace it when damaged, and otherwise keep it in tip-top shape.

Main Takeaways

  • The salt cell is a part of a salt chlorinator that converts the dissolved salt into chlorine with a low-level electrical charge.
  • Signs of a potential problem with your salt cell include: Check Salt message displays even though salt levels are fine, Cell Warning light displays constantly, voltage is higher than normal, amperage is irregular, and the SCG isn’t producing chlorine.
  • Potential problems that can occur that are unrelated to salt cells are: harsh sunlight and low CYA levels, faulty filter, low pH, high phosphate levels, and water temperature below 50 degrees.
  • To replace a salt cell, shut off the power, loosen the old salt cell and tighten the new one by hand, make sure O-rings are in place, and then reconnect it to the control box.

Salt Systems Explained

A saltwater pool is powered by a salt chlorinator. It’s a system that turns a small amount of salt into chlorine, which keeps your pool clean. Chlorine is produced naturally instead of added by the pool owners.

A salt chlorinator has two components:

  • Control Box
  • Salt Cells

The control box is the brain of the operation. It generates the electricity used by the cell. Additionally, it houses an LCD screen or other system to display alerts and other info. The control box connects to the home’s electrical system.

The salt cell is an electrolytic converter installed on the return line behind the filter, heater, and pump. When water passes through the cell, a low-level electrical charge converts dissolved salt into chlorine. The chlorinated water returns to the pool, killing bacteria and preventing algae growth.

It’s a cylinder, usually around a foot-and-a-half long, placed into the water line. It’s typically located a few feet from the control box, which it’s connected to with a cord.

Signs of a Potential Problem

Understanding when a salt cell might need replacement isn’t always easy. Many problems that can occur within the system produce similar symptoms to one another. New saltwater pool owners often mistakenly blame a faulty cell when the real issue lies elsewhere.

That said, here are solid indications the salt cell likely needs cleaning, repair, or replacement:

  • The power center displays a Check Salt message. However, a water sample shows normal salt levels.
  • The Cell Warning light displays consistently, shutting off for only a short while after cleaning.
  • The voltage is higher than normal.
  • Amperage is irregular (it should normally be zero or just slightly above)
  • The SCG isn’t producing chlorine (which could potentially indicate a cell issue)

Timing plays an important role. Generally, a salt cell lasts for about 10,000 hours, which is usually around five years for most home pool owners. If your cell is close to or exceeds the 10,000-hour mark, and you notice any of the above signs, it could very well need replacement. Except if the main issue is a lack of chlorine, which alone isn’t enough to indicate a salt cell problem.

False Alarm? How to Check

If you suspect an issue with your salt cell, run through the following checklist:

Is it time to clean the cell? Many systems send an Inspect Cell alert every 500 hours, which is the recommended cleaning schedule.

Is the salt cell system turned on? You can have the unit powered up but not generating chlorine. Make sure it’s set to Auto or whatever is specific to your brand.

Are all the connections tight? Double-check the connections at the cell and the control box. Some cells have internal connections you’ll need to check, too.

What’s the salt level? Many SCGs will shut off automatically if the salt level becomes excessively high or low. The recommended range is between 2,500 and 3,500, although auto-shutoff levels can vary. If you don’t know how to check for high or low salt levels, read my guide on how to test the salt level in your pool.

What’s the temperature? If the pool water is below 50 degrees, less chlorine is required, and some systems will shut off automatically.

Potential Problems Unrelated to Salt Cells

Before replacing your salt cell, consider these other common issues that cause chlorine levels to drop:

  • Harsh sunlight combined with low levels of pool stabilizer (cyanuric acid)
  • Faulty filter
  • Low pH balance
  • Phosphate levels that exceed 100 parts per million
  • Water temperature below 50 degrees

Try to rule out all the simple stuff first, so you don’t replace your salt cell needlessly.

Interpreting LCD Messages

Your salt system will try to alert you when something’s wrong. Each brand uses slightly different messaging, so be sure to refer to your owner’s manual for all the details. Some models display a word, while others might change the color of a word (such as from green to red to indicate a problem).

Look for these two types of alerts:

  • Inspect Cell, Cell, etc.
  • No Flow or Flow

A cell alert indicates that the salt cell has slowed or stopped working. It doesn’t necessarily mean the cell is faulty and needs replacement. Instead, it might just need a thorough cleaning.

Important: Many models display the Inspect Cell alert every 500 hours as a cleaning reminder. After checking the cell and cleaning it, you’ll want to reset this reminder.

A flow alert indicates water is unable to flow through the system properly. This isn’t a salt cell issue. A flow alert typically means either the pump isn’t running or the flow switch is damaged.

Maintenance and Cleaning

Keeping your salt cell clean greatly helps extend its lifespan. The main issue is calcium buildup, also called scale. It impairs the ability of the cell to create chlorine effectively.

You want to clean the cell every 500 hours, which is usually about every three months. As mentioned above, many systems will send you a cleaning reminder. To help reduce buildup, maintain the following levels:

  • pH between 7.2 and 7.8
  • Calcium between 200 and 400 ppm

If your pool is properly chemically balanced, you should only need to clean it three or four times a year.

Cleaning Your Salt Cell in 7 Steps

  1. Turn off the power to the control box, either at the box itself or through the breaker panel. Remove the cord connecting the salt system to the box. Note: the only part that isn’t waterproof is the connection that plugs into the box.
  2. Unthread the two connections to remove the salt cell. You want to look inside at the metal plates. Scale is an obvious buildup of hard, white material.
  3. Rinse the cell with a garden hose. Although it likely won’t wash away much of the buildup, it does remove any loose debris that can accumulate.
  4. Next, prepare the cleaning solution. Fill a plastic bucket with a solution of one part hydrochloric acid to four parts tap water. You can find hydrochloric acid at most pool supply stores, or you can also buy pre-made cleaners. (Wear gloves and goggles!)
  5. Your system should include a cleaning stand. Place the cell into the stand, with the cord section on the bottom, ensuring it’s thoroughly cleaned.
  6. Pour the solution into the cell. It should cover the blades entirely. Let it soak for about 15 minutes, or until the fizzing and bubbling stops.
  7. Pour the mixture into the bucket or otherwise dispose of it safely. Rinse the cell and reinstall it into the system (either end of the cell can connect to either part of the tube).

If you’ve identified the problem as a salt cell issue, and a cleaning doesn’t fix it, then replacement might be necessary.

Replacing a Salt Cell

Cleaning the cell isn’t difficult, but replacing one is even easier. As with cleaning, start by shutting off the power to the control box.

If necessary, you can use a wrench to loosen the old salt cell. But only tighten the new one by hand. Using tools on the plastic parts can cause damage.

Make sure the O-rings are in place. They ensure the cell connects correctly to the line. Although it seems simple, forgetting or improperly placing the O-rings is a common cause of connection problems.

After installing the new cell, you’ll need to reconnect it to the control box. Ensure it fits tightly. Refer to your user’s manual for specific setup details. Don’t forget to schedule a cleaning reminder.

Get My Free Pool Care Checklist

Download my free, printable pool maintenance checklist to help you accomplish regular pool care tasks for any type of swimming pool.

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Final Thoughts

If you keep your salt cell clean and properly maintained, it should work without a problem for at least five years. Always pay attention to any warning messages, and ensure your pool is chemically balanced. Fortunately, keeping your salt cell working great is pretty easy, so your pool is always ready to enjoy!

Questions about salt cell replacement? Shoot me a message.

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