Water Conditioning & Purification Magazine

Ask the Expert

The long and short of softening

Question: Could you please explain why water treated by a softener typically will show an increase in sodium, and a decrease in chlorides, when softener salt is composed of sodium chloride? Thank you.

Larry C. Aldridge
Hartville, Ohio

Answer: A “short” answer for you might be that, in the ion exchange process, softeners/conditioners use saltsodium chloride (NaCl) or potassium chloride (KCl)—to regenerate the resins that remove contaminants from the water stream. This is done by ionic selectivity based upon the electronic charge or valence of the compounds being removed, which are “attracted to” or “regenerated off” of a resin bead. As the bead loads up with contaminants that are adsorbed or absorbed onto it, sodium or potassium is released from the bead in “exchange” for the undesirable element. Don’t forget, this is in very small quantities. When the softener is regenerated, water from a brine tank containing pellets of salt—NaCl or KCl—is flowed through the resin bed and, because of the concentration, the undesirable contaminants are “backwashed” off of the resin in exchange for the Na or K part of the salt. The chlorides also are sent to waste in the backwash water. I believe that provides the simple answer to your question, even if it’s not short. Keep in mind, the longer answer is more complicated and requires a broader understanding of water chemistry.

Reducing septic system impacts

Question: I am trying to determine which way to go: water softener or purifier of some sort.

Our problem is hard water, which is not affecting much of anything except our skin after showering, my wife’s hair and some items in the wash (despite use of Downy and other similar products). We are on a septic/leach field system so we do not want to use backflushing systems, and I am a bit concerned about use of salt in this system also (fear of killing those nifty little enzymes). I am not sure if the latter is a legitimate concern or not.

This is a small population area and providers seem to be Kinetico, Culligan and Sears. I do not really trust the sales people as they are there to sell their products only and may not even know the full story of water conditioning. So far, I have been unable to find any publications that are definitive. I’m hoping you can steer me in the right direction. Thank you.

Dennis Jones
Stevensville, Montana

Answer: Extensive studies have indicated that the brine from water softeners will not have a significant effect on septic systems. Keep in mind that watching your use of detergents, cleaners, shampoos, soaps and other items that may go into your septic tank via shower, laundry, dishwasher or garbage disposal can sharply reduce the load you put on your system. These can be significantly more damaging than softener discharge. Opt for more “natural” low-phosphate, low-chlorides products where possible—and compost waste or put it in the garbage rather than run it down the disposal. With respect to water treatment, I would suggest you try to find someone at a dealership that you feel is technically competent, and whose opinion you trust. Take a little time to get to know them. Research what they tell you. Compare and contrast. Trade journals such as WC&P, as well as the Water Quality Association (www.wqa.org), are committed to providing educational information to readers/members, and many professionals in this industry are knowledgeable and committed to providing objective and accurate information to the consumer.

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