Salt Chlorinator and Salt Cell Maintenance
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brians-pool

I was visiting some friends this weekend in Phoenix, and noticed his swimming pool to be a little dark and cloudy.

“Yeah, it went green a few weeks ago – I shocked it, but I can’t get the water to clear”, Brian said.

We tested the water, found the chlorine level to be zero. Brian has a SWG (salt water generator), so we went right to the unit. The salt level in the pool was a bit low, but not by very much. “When’s the last time you cleaned the salt cell?” I asked.

When he looked like a little guilty, we loosened the unions on the salt cell and took a look inside the chamber. Arizona is known for hard water, so when we found calcium deposits between the plates of the salt cell, it was no surprise.

Cleaning your Salt Cell

The number one maintenance item for a salt water chlorinator is to clean the salt cell regularly, every 2-6 months, but only as needed. Mineral deposits bridge the space between the metal plates, and not just in hard water areas.dirty-salt-cell

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 build-up on the salt cell can permanently damage the coatings on the plates, leading to cell failure.

Many new pool salt systems are self-cleaning. A great feature, 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. Afterwards, 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.

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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 3 sensor shown here.

flow-sensorAfter removing the sensor from the tee fitting, I scrubbed it with the textured side of a dish sponge, to clean all 3 sensor probes, or spots on the underside. We reinserted the sensor into the pipe and turned everything back on – 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 and took them over to the shade, had a seat to hose them off – they were very dirty.

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 lbs. We found the air bleeder assembly was clogged with debris, giving false readings.

Winter Salt Cell Maintenance

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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 fifties, 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

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Don’t overwork your salt cell – keep your chlorine level as low as you need to maintain clean and clear pool water.

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Use Conditioner or Stabilizer, to help protect your chlorine level from the sun, and again, to prevent overworking the cell.

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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.

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Keep the salt level proper in the pool. You’ll need to add more salt once or twice per year.

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.

If you have any questions on salt chlorinator maintenance, leave a comment below, or give any one of our salty pool dogs a call for some help!

davy-merino
Davy Merino
InTheSwim Blog Editor


Comments

Salt Chlorinator and Salt Cell Maintenance — 15 Comments

  1. Hi Davey, my Hayward Goldline Aqua Rite salt cell chlorinator (clean and less than 2 years old) is producing TOO MUCH chlorine.I have a relatively small pool (12,000 gal). I set it to the lowest possible output percentage and it still over produces. I’m only running my pump for 6 hours or less but my test readings for chlorine are way hi. Is their anything I can do other than turn the chlorinator off and on and monitor it constantly??

    • Hi Gary, are you measuring Free chlorine or Total chlorine? You may be measuring a high level of combined chlorine (chloramines) in the pool, which would indicate the need for shocking the pool. Also I would ask if your reagents or strips are reliable, and not old, just to be sure.

      If all is good with those things, and it is producing too much free chlorine, perhaps you can reduce the cyanuric acid (stabilizer) level in the pool (if over 50 ppm). As the weather gets warmer and the water gets warmer, it may settle down, or the chlorine demand should go up, and become more manageable. If you use an automatic pool cover, opening daily to expose the pool to sun and air can also help for now. But yeah, for a 12000 gallon pool, I could see how it could happen.

  2. I just had a pool installed and the contractor hooked up the sand filter backwards and ran it for a week like that pushing sand out of the filter through the Heater and Salt Cell – would the sand damage the cell and heater??

    • Hi, sand can be abrasive, and could have damaged the coatings on the salt cell, or possibly nicked up the heat exchanger in the heater, but there may be no way to know for sure, unless you can visually see something. There really should not be any possible way to plumb a sand filter that would push sand out of the filter, but if the tank was overfilled (too much sand), if it was plumbed in a backwards, (backwashing and returning to the pool), then excess sand can be expelled, but probably not much, a few lbs. maybe?

  3. Hi, my two year old self cleaning salt water chlorinator usually alternates from positive to negative (as it should) however it is stuck in negative. How can i fix this, and is it damaging my cell.It is a Davey ChloroMatic MCS24C.
    I would appreciate any suggestions.
    John

    • Hi John, not a question I’ve heard before, but I would try to manual clean the salt cell, by soaking in a 10:1 Water to Acid mix, to remove any calcium. Also make sure that the water is balanced with good levels of calcium hardness, alkalinity, pH and cyanuric acid (stabilizer). Inspect the wire terminals, and clean with a wire brush if any deposits or discoloration is observed. If that doesn’t help, you may have a bad relay on the circuit board, causing it not to switch back to positive. If you still have problems – check with Davey – http://www.davey.com.au/services-and-support

    • Hi Troy, if you have tried cleaning the cell already (even though you don’t see deposits, it still could be ‘filmed’), and it still doesn’t work, 2) Check water temp (cell won’t work under about 60 degrees F), Check salt level (cell won’t work under about 3000 ppm salinity), and finally 3) check your water flow to be sure that the filter or baskets aren’t clogged, or water is not being bypassed – you can also check the flow sensor for correct placement to the water flow.

  4. Davy, I cleaned my cell but accidentally used a much higher muriatic acid ratio. Now, it consistently says my salt is low. I don’t want to keep on adding too much salt…Did I ruin the cell?

    • Hi Tom, I don’t think that a failing salt cell will give a low salt error. Salt Cells can take a good acid washing, you probably are ok there. Your salt sensor could need cleaning though. They can develop scale which affects readings. Not sure which type of salt system you have, but it has a salt sensor in contact with the water, sometimes it’s combined with the flow and temp sensor, into one 3-way sensor. Just clean off the silver contacts after removing the sensor. In some cases they also go bad :-(. Also check the cable from the sensor to the controller, and be sure it’s plugged in securely. You can buy salt strips to check (and in some cases calibrate) your salt sensor. It could be correct, telling you that salt is low. It takes a good bit of salt to move the needle, you can use the Pentair Salinity Calculator to determine salt demand, or how much salt to add to the pool – http://www.pentairpool.com/support/calculators/salinity-calculator.htm

  5. Hi Davy. My cell is of an old type that cannot be put in a bath or hosed out because it is not possible to detach it from the power supply (without an electrician). The best I can do is put the 1:15 acid mix into the cell and let it sit. I’ve done this a few dozen times now and it has little effect on the significant calcium deposits. Do you have any advice for me?

    • Hi Jeremy. A 1:15 mix is pretty tame, probably what the manufacturer recommends, but yeah, it won’t do much on heavy deposits. Try a 1:10, or even a 1:5 if the 1:10 doesnt’ work. Another option would be to have it rewired somehow, so that you could unplug it to clean it, which may be more effective, with the help of a hose, or small soft brush.

  6. I just replaced my salt cell and the flow sensor, however I’ve noticed that the check flow light comes on as soon as my multi phase motor speed drops. I suspect that the flow becomes insufficient for the flow sensor contact contact points to engage. Does this affect the salt converters ability to produce chlorine? I’m not sure if the flow switch also controls the engaging of the converter tube. The chlorine level is almost non existent. The water here in Florida (unheated) is in the 50-60 degree range.

    • Hi Bob; most salt cells will operate just fine on low speed of 1725 RPM. If your check flow light is on, that would indicate that the flow sensor is not closed, which means that your salt cell is not producing chlorine. First thing to do is to clean or backwash the filter and pump basket, and rule out any clogged pipe or pump impeller, or bypass valves, pool water level – anything that would reduce water flow. If that’s all good, your salt cell should operate. If not, you may be able to bend the contact points closer together on the flow switch. Check that the sensor cord is connected properly into the controller. And, make sure the sensor is installed correctly in the direction of the water flow, aligned with the arrow. If it still doesn’t work, and your pump speed is adjustable, you can raise the RPM slightly to see if the low flow light turns off. Depending on your salt system, there may be other tweaks that you can do, but that may require contacting the manufacturer. As with most salt systems, this is one of those occasions where having some granular pool shock or tablets on hand can really save the day, and allow you to maintain chlorine levels when the salt system (or the pump, plumbing or filter) not operating.

  7. Pingback: Saltwater Pool System: A Good Fit for Your Family? | InTheSwim Pool Blog

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