Cleaning Water Softener Resin: How Regeneration Works and Why It Matters

It’s considered that about 30% of the people in the US that live with hard water and use water softener systems (Source: Homewater 101). Therefore, it’s important to learn how  you can keep your system clean in order to maintain its full functionality and support your daily life.

Water softeners are based on an ion exchange column containing a resin loaded with sodium that becomes saturated, and requires to be regenerated or cleaned from time to time, it’s estimated that the cleaning will be necessary every 6-12 months depending on the water hardness. By passing a highly concentrated solution through the column in a countercurrent flow, the very high concentration of sodium ions reverses the ion exchange equilibrium, displacing the calcium and magnesium accumulated and carrying them away dissolved in the wastewater restoring the functional capacity of the resin.

Laura, mother of five, consulted her system manual to learn the step by step to clean her softener system, and after a quick review to the manual she managed to simplify them: First, wait until the salt level in the brine tank is low; Identify the resin volume in your softener to understand how much resin cleaner you need, note that for every quarter gallon of resin inside your water softener you will need to use a third of an ounce of resin cleaner solution; then pour the resin cleaner directly into the brine tank and perform the counterflow process to complete the cleaning for 10 min so your resin is rinsed. She understood that it wasn’t as difficult as she thought it would be.

Fundamentals for the water softener resin cleaning process

The functional resin used in your water softener is positively charged, and also has some negatively charged groups, such as SO, so that the material is electrically neutral. In the normal flux, as hard water passes through, the calcium and magnesium ions, which are more positively charged and have a greater affinity for the resin, displace the sodium until the column is saturated. This is when it’s time to clean the water softener resin, by removing the calcium and magnesium accumulated and restarting the process.

This cleaning process is also called resin regeneration and is carried out by flowing a saline solution, a brine containing high concentrations of salt (sodium chloride) in a countercurrent direction through the column, as shown in the following diagram:

The brine itself would not work as sodium is weaker in charge terms compared to the calcium and the magnesium, so for this process to succeed, a chemical game of forces is needed:

• The solution has to be a super-concentrated “soup” of Na+ ions.
• The high concentration promotes the ion exchange process to be reversed
• The sodium ions are able to displace the calcium and magnesium from the resin, releasing them in a dissolved form down the drain and effectively rinsing the resin.

Most of the softener systems are built with a special tank for salt to complete the cleaning process when needed, and they recommend cleaning the resin tank frequently to avoid accumulation of residues as well as checking all the valves and connections to prevent pressure problems while doing the cleaning. The industry has it all considered so you can find what you need in your favorite home improvement supply store, for example high quality sodium, that can be dissolved in water, for an accessible cost depending on your personal needs. Everything already considered for maximizing the life of your softener column and maintaining the resin’s capacity to do its job.

The other day a friend of mine, Mario, suggested that instead of spending any money cleaning my softener system, he used only vinegar and worked perfectly fine. I was wondering if this method would really work.

Other methods for cleaning the resin in a water softener suggested often presented as low-cost, do-it-yourself solutions are using vinegar like in Mario´s example. However, it’s important to remember that common vinegar is a weak acid and therefore will not have the necessary chemical effect to remove calcium and magnesium from the resin as brine does. While vinegar might remove superficial mineral deposits from the resin or the column, similar to how soaking a showerhead in vinegar overnight removes limescale, this process will not regenerate the resin; that is, it will not restore its function or effectiveness in the ion exchange process. Furthermore, the constant use of acid in a sensitive system like a water softener column can corrode and damage some of its components.

Final Thoughts

Cleaning your resin frequently and maintaining your system in the right conditions will lead to continued benefits:

• Improving the life cycle of your tuberies and appliances
• Improving your hair and skin health
• Making your clothes softer after wash
• Avoiding stains in kitchen tools or even while washing your car.

Homemade methods using vinegar, being a weak acid, can remove superficial mineral deposits, but they do not provide the necessary chemical effect to regenerate the resin or restore its ion exchange capacity.

The systems include a salt tank, and so you can easily purchase salts in tablet, granule, or block form, at a relatively affordable cost per bag. Allowing periodic regeneration of the resin and extending the lifespan of your system.

FAQ:

Can I do this myself or do I need a specialist?

Where can I get this brine?

You can always search in your favorite home improvement supply store. Most of them offer high quality sodium in the shape of tablets, pellets or rocks that can be dissolved in the water of your brine tank.

How much do I need to pay for the brine pellets?

An approximate found is about $20-$30 dollars per 40 Lb, however this is just an estimate. All these products are highly affordable and they come in different versions, so the price will depend on the amount purchased.