How do Water Softeners Work?

The solution to the hard water problem is to get rid of the calcium and magnesium.  There are chemical treatments that do this, but Culligan has determined that the healthiest and most effective method is an ion exchange water softener.

A water softener is a mechanical appliance that is plumbed into your home’s water supply system, usually at the water main entry.  Softeners trade the “hard” particles dissolved in the water for “soft” particles.  The process is called ion exchange.

The main component of a water softener is the ion exchange tank. It is filled with small polystyrene beads, also known as resin. The beads carry a negative charge.  The positively charged calcium (Ca2+) and magnesium (Mg2+) ions that cause hardness are attracted to the negatively charged resin beads. As hard water passes through the ion exchange tank, the calcium and magnesium trade places with sodium ions on the resin beads. Sodium ions are supplied to the resin from dissolved sodium chloride (salt), also called brine.  Sodium ions have a lower positive charge and are held loosely on the resin. They are easily replaced by the stronger charge of the calcium and magnesium ions. During this process the freed sodium ions are released or “traded” to the water.

After “trading” a large quantity of hard water ions the exchange medium becomes saturated with the calcium and magnesium ions. It has given up all of its “soft” ions and is said to be “exhausted.”  When this occurs, the exchange medium must be recharged, also called regeneration. To recharge the resin the softener is back-flushed with the salt brine solution from the salt storage tank. During a back-flush the brine solution rinses the resin, overwhelming the bond between the “hard” ions and the resin, thus replacing the calcium and magnesium ions on the exchange medium with fresh sodium ions from the salt solution.  The calcium, magnesium, and chloride from the salt are then sent down the drain during the softeners final rinse.  A common misconception is that this process adds salt to the water, this is not the case.  The salt is broken down at the molecular level during the regeneration process into its components, sodium and chloride.  The chloride is washed away with the calcium and magnesium.  This method of hardness removal is very efficient and can be repeated over and over, again and again, for years. Culligans’ resin beads, as well as many of the other softener components come with a lifetime limited warranty for the original purchaser.

Maintenance of water softeners is mostly limited to restocking the salt supply for the brine solution. Newer softeners are very efficient and use minimal salt.  Of course the actual amount will vary with the hardness of the source water and the amount of water used per month.  In addition to regular refills the salt storage tank may require occasional cleaning. The frequency of cleaning depends on the amount and purity of the salt used in the softening process. The brine valve and float assembly should also be checked and cleaned at the same time. Over time other impurities in the water such as iron, sediment, chlorine and chloramines can affect the ability of the resin to be regenerated. Culligan recommends periodic “reconditioning” of the ion exchange tank, again the frequency is determined by the type and amount of the impurities present in the source water. Other components of water softeners do wear over time.  Rubber gaskets, fittings and moving plastic parts will eventually need replaced. But all in all an ion exchange water softener is the most efficient and cost effective method of eliminating the problems associated with hard water.  Get better water in your life with water solutions from Culligan. The first step is a No Obligation Water Analysis.