How does a water softener really work?

How does a water softener really work?
By Charlie Dietz
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How does a water softener really work?

I often get calls from people concerned about their water softener operation.  I have found that most people don’t understand how a water softener works.  This blog is intended to give a brief description on how a water softener works.

Water softeners like the Matrixx Water Softener With Smartphone Programming (pictured belwo) use a process called ion exchange.  Every element in your water is made up of ions.  A water softener exchanges scaling ions (calcium and magnesium) with non-scaling ions (sodium).  Ions can be both positively (cation) and negatively (anion) charged.  Water softeners use cation resin to capture scaling ions.

This media is in the main pressure tank of a water softener.  A water softener has 3 components.  The pressure tank (cation media tank), a control valve (controls the flow of the water through the system) and a brine tank (salt tank to hold a salt solution for cation media regeneration).  In the service mode water passes through the control valve and flows through the pressure tank and cation media bed, then out to your home.  As the water passes through the cation media, calcium and magnesium (hardness) ions are attracted to the media, and when the ions reach the media they are captured by it.

When they are captured by the media, the sodium ion on the media is released.  This is the “exchange” process.  Magnesium and calcium are exchanged for sodium.  After a set number of gallons pass through the media, the media becomes impacted by the calcium and magnesium and there is no longer any sodium left on the media to exchange.

When this happens the water softener must be regenerated.  This is where the brine (salt) tank comes into play.  The salt tank is only used during a regeneration process.  When a water softener regenerates it is flushing the calcium and magnesium ions out of the pressure tank where the media has collected them.  Typically there is a backwash cycle first that will flush all sediment and precipitated ions out of the pressure tank.  Once that process is complete the next cycle is the “brine draw” cycle.  During this cycle the brine (salt) solution is drawn in the control valve and directed through the media bed at a slow steady rate.

As the salt solution passes through the media the calcium and magnesium ions collected on the media are “exchanged” for sodium ions in the brine solution.  Salt is made up of sodium and chloride.  The sodium is collected on the media, and the chloride is flushed to the drain with the calcium and magnesium ions that have been released from the media.  Once the “brine draw” cycle is complete, the control valve rinses the media to remove the excess salt solution.  The very last cycle is the “brine fill” cycle.  During this cycle water is directed back to the salt tank to make up a concentrated salt solution for the next regeneration.

So basically we exchange the hardness for sodium, until the hardness has overwhelmed the media, then we apply a salt solution and exchange the hardness collected on the media for sodium so the media has the ability to capture the hardness again.  The core of the water softener is the cation media.  If you softener isn’t working, either the media is very old and is breaking down, or the salt solution is not being conveyed through the media during a regeneration.

The most obvious sign of a problem is the way the water feels but the most common cause is the salt solution is not being used properly.  This can be because of improper settings or improper sizing, but most of the time it is because there is a clog in the brine draw system.  The most common indicator is that the salt tank is overfilling with water.  This is because the brine system is clogged or not working, so the salt solution isn’t pulled into the cation media pressure tank.

Then when the system goes to “brine fill” the water level in the salt tank continues to rise because no water is ever being removed.  If this happens the most common cause is the tubing from the salt tank to the control valve is loose and sucking air in instead of the salt solution.  90% of the time this line is the cause of water softener failure.  However, on water feed systems with high levels of sediment or iron the cause may be clogging from these elements.  If you have high sediment or iron, they should be removed before the water enters the softener with a 5 micron sediment filter, such as our Magna Filter.

So if the water isn’t soft, check the water level in the salt tank.  If it is overfull, you most likely have a loose brine tube or a clog.  Once that is fixed the system will regenerate properly and the soft water will return.  This is not intended to make you an expert.  It is to help you understand the process.  If you want to know more about the operation feel free to give me a call at 1-800-608-8792.

Tip:  Whenever you have a problem and the water softener hasn’t been regenerating properly, it is recommended that you regenerate your softener 2-3 times back to back once the water softener is repaired.  Typically you won’t know how may gallons of water has passed through the softener untreated so we regenerate a few times in a row to ensure we are back to “ground zero”.

Matrixx Water Softener With Smartphone Programming
September 2, 2019
Braden Bills
August 23, 2019 at 10:16 AM
I want to make sure that my home doesn't have hard water. It makes sense that getting a water softener would help! It's interesting that they help exchange out chemicals in the hard water to make it softer. That's definitely worth getting.
Mark Timmons
September 2, 2019 at 3:53 PM
Great idea!
December 21, 2019 at 3:02 PM
Hi - we're loving our Matrix water softener and charcoal filter! Had um for about 8 months. I'm thinking about trying potassium chloride instead of regular salt. I know the KCl costs more, but is there just a 1 to 1 swap? Would I be using the same amount of KCl as I'm now using NaCl? I read on-line that it takes more KCl. Thanks very much. Erich
Mark Timmons
December 22, 2019 at 10:22 AM
I would recommend shortening your capacity by about 10%. As an example, if you are regenerating every 1,000 gallons, lower it to 900. Potassium is a little less efficient than sodium.
Robert Clark
July 2, 2020 at 4:05 AM
I have read somewhere they said water softeners often work like magnets. It basically works based on the fact that negative and positive things attract. As mentioned earlier, magnesium and calcium are among the major culprits of producing hard water. That are charged positively. Is that right?
Mark Timmons
July 4, 2020 at 9:30 AM
To compare them to positive and negative charges of magnets is inaccurate. However, cations are ions with a net positive charge. As it relates to hardness in water, calcium, and magnesium are the two ions that form hardness. Sodium or potassium are also positively charged ions and during cation exchange, the sodium or potassium exchanges with the calcium and magnesium.
Robert Clark
July 4, 2020 at 9:30 AM
In here: . I have been read it. I think it useful. How do you think about this?
Mark Timmons
July 31, 2020 at 7:10 AM
This is what is called a "Affiliate" website. They make a commission on the products listed. They even say this: "RV Web Network is reader-supported. When you purchase through our links, we may earn a commission." They go on to say: " is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to As an Amazon Associate I earn from qualifying purchases." I find it interesting that two of the mini softeners listed are by a company that is now out of business. It is an interesting site, but there is a lot of misinformation, such as: "You can also go for the electronic water system, which makes use of electrical wires as a means of changing the charge associated with the hard mineral ions. It is a bit similar to the salt-free units as it can’t completely get rid of hard minerals and soften the water." THAT IS TOTALLY FALSE! "Another option is the magnetic water system. It is referred to as a magnetic softener as it makes use of strong magnets attached to the device’s pipe. With the aid of the magnets, the way mineral ions are charged will be disrupted. This can prevent possible clogs in the plumbing pipes and fixtures." BOGUS! It gets better as they say "water softeners work like magnets." That's not how they work at all - they work on the principle of ion-exchange. They also talk about "salt-free water softeners" which do not exist. They are purely fictional and are the fantasies of unscrupulous marketers. There is a lot of information here. That helps the site rank higher and helps him make more money, but with the disinformation involved, he is doing the consumer a disservice.