Salt Chlorinator and Salt Cell Maintenance

Salt cells are an essential part of a pool's filtration system, responsible for producing the chlorine needed to keep the water clean and safe for swimming. Regular maintenance of these cells is essential to ensure their optimal performance and longevity.

What Causes Calcium Buildup on a Salt Cell?

Ironically, the salts that you add to the pool are the same salts that will deposit themselves onto your salt cell. The number one cause of this is high pH levels. Adding salt to the pool will raise the pH level in the pool, and the sodium hypochlorite that a saltwater chlorinator produces will also raise pH. Maintaining your pH level on the low side, around 7.2-7.4, will reduce scale buildup on your salt cell.

High total alkalinity levels in your pool can also be a factor. High levels of carbonates can make it difficult to reduce your pH level and also contribute to the scaly stuff that is attracted to the electrically charged metallic plates. Maintain your TA level on the low side as well, around 80-90 ppm.

High calcium hardness levels in a pool will accelerate scale buildup on your salt cell; you probably could have assumed that much. Maintain your calcium hardness levels on the low side, around 180-200 ppm.

Run time of your salt chlorinator can also increase scale buildup on your salt cell. The longer the salt system is operating, the more time it has to attract calcium salts. Keeping your salt level up, at the proper level, and using stabilizer or conditioner to shield the chlorine it produces from the sun will reduce necessary run time of your salt system.

Cleaning Your Salt Cell

The number one maintenance item for a salt water chlorinator is to clean the salt cell regularly, every two to six months, but only as needed. Mineral deposits bridge the space between the metal plates, and not just in hard water areas.

Calcium is naturally attracted to the electrically charged plates, and when they build up too much, it blocks the ability for electrolysis to occur. Over time, too much buildup on the salt cell can permanently damage the coatings on the plates, leading to cell failure.

Many new pool salt systems are self-cleaning. They do this by reversing the polarity or charge of the metal plates, repelling the attracted mineral deposits, which is swept away by the rushing water, before it can attach to an oppositely charged plate.

We cleaned Brian's salt cell by filling a small bucket with 1 gallon of water mixed with 1 cup of muriatic acid. We submerged the cell in the bucket and left it for 10 minutes, then returned and flipped it over for a few more minutes.

We then flushed the cell with the garden hose and could see clearly through the cell that the deposits had been successfully removed. Afterward, we dumped the acid solution into the pool. We then shocked the pool with granular chlorine to raise the chlorine quickly; it was, after all, 108 degrees outside.

Some brands of salt systems will have end caps that you can purchase, so you can then fill up the salt cell with an acid mix. You can also use a winter plug to block one end of the cell and then pour the acid mix into the cell, or just use a bucket.

You will see bubbling and fizzing as the acid works to dissolve the scale. When the fizzing stops, the cleaning is complete. Immediately afterward, rinse the salt cell thoroughly to remove the traces of acid. I like to take it over to the pool, dunk the entire cell in the pool and swish around for about 30 seconds.

Some things NOT to do when cleaning your salt cell:

  1. Don't soak the cell in acid for too long, over 20 minutes.
  2. Don't increase the acid strength, use a 15:1 solution.
  3. Don't use metal tools to scrape off salt cell deposits.
  4. Don't clean the salt cell if it's not visibly coated.

After the salt cell cleaning, we reconnected the unions and turned the filter pump back on, and noticed the glow of the "No Flow" indicator on the control panel. I checked the cable from the sensor to the control panel, which looked good, and it was also connected into the panel snugly. Time to inspect and clean the flow sensor.

Cleaning the Flow Sensor

Although rare, in hard water areas, the flow sensor can also develop deposits on the terminals. A flow sensor is used with salt systems to make sure that water flow is sufficient for operation. They also usually sense water temperature and the salt level in the pool, like the three sensor shown here.

After removing the sensor from the tee fitting, I scrubbed it with the textured side of a dish sponge to clean all three sensor probes, or spots on the underside. We reinserted the sensor into the pipe and turned everything back on. We still got the "No Flow" error!

We knew there was flow, since the pump was on, and there was 15 psi on the filter pressure gauge. "Time to clean the filter cartridges?" I asked. He said he usually waits until 20 psi to clean, but "sure, we can try that". So, we pulled out the filter cartridges, took them over to the shade, and had a seat to hose them off. They were very dirty.

We reinserted the filters and started the system back up. The pressure gauge still read 15 psi until I flicked it with my finger, and then it dropped to 10 pounds. We found the air bleeder assembly was clogged with debris, giving false readings.

Winter Salt Cell Maintenance

You may not know this, but most salt cells won't work well in water temperatures less than 60 degrees. For this reason, they may have trouble creating enough chlorine in the winter, for Sunbelt pools. They can also be overworked in such temperatures, leading to a shorter lifespan.

If your Sunbelt pool temperature drops into the 50s, it would be best to shut off the salt system and use another chlorination method, like chlorine tablets, until the water heats up again.

For pools in the Snowbelt, it may be advised to remove the salt cell after blowing the lines, and store it indoors. The sensor can also be removed or it can be wrapped in plastic for the winter.

Other Salt Cell Maintenance Tips

  • Don't overwork your salt cell. Keep your chlorine level as low as you need to maintain clean and clear pool water.
  • Use conditioner or stabilizer to help protect your chlorine level from the sun, and again, to prevent overworking the cell.
  • Keep your pH balanced. If below 7.2, it can etch the salt cell, and if above 7.6, it will reduce the chlorine's effectiveness.
  • Keep the salt level proper in the pool. You'll need to add more salt once or twice per year.

In summary, to ensure peak performance of your salt cell:

  • Maintain proper salt levels. Add to replace salt lost by splash out, backwashing or leaks.
  • Maintain low levels of pH, total alkalinity and calcium hardness.
  • Maintain proper levels of cyanuric acid, stabilizer to reduce demand on your salt cell.
  • Inspect and clean your salt cell regularly to remove any scale buildup.
  • Keep your chlorine level as low as possible. Test the water to maintain 1.0-2.0 ppm.
  • Use the super-chlorinate function only as needed to remove combined chlorine levels.

Pool salt systems are real-time savers, but they do need occasional maintenance to keep them working properly and to prolong the life of your salt cell.

Eventually, you'll need a new salt cell. You'll know it's time when the chlorine output drops to low levels, despite a clean cell and sensor, proper water balance, salt levels and water temperature.

In The Swim makes every effort to provide accurate recommendations based upon current ANSI/APSP/ICC-5 2011 (R2022) standards, but codes and regulations change, and In The Swim assumes no liability for any omissions or errors in this article or the outcome of any project. You must always exercise reasonable caution, carefully read the label on all products, follow all product directions, follow any current codes and regulations that may apply, and consult with a licensed professional if in doubt about any procedures. In The Swim assumes no legal responsibility for your reliance or interpretation of the data contained herein, and makes no representations or warranties of any kind concerning the quality, safety, or suitability of the information, whether express or implied, including, without limitation, any implied warranties of merchantability or fitness for a particular purpose.