However, if you want to understand the Austin office water filtration science behind salt-free water softeners, the information and science behind them is not so clear. One online seller of salt-free water softeners on their website, say this is how they say their process works:

“The process our salt-free water softener media use water flow to naturally prevent limescale build up. The process takes hard water (calcium and magnesium) and transforms the ions into microscopic nanocrystals. This suspends the particles so that it cannot “stick” or cause scale while the water travels through.”

Another online seller of “salt-free water softeners” is Nuvoh2o. They describe how their process works here:

“First, instead of removing beneficial minerals like old-fashioned salt softeners, the NuvoH2O system binds and isolates the hard mineral ions with a process known as chelation. Once bounded to CitraCharge®, NuvoH2O's binding agent, the mineral cannot form scale.

So, that sounds pretty good, doesn't it? US Water Systems also sells a Salt-Free System called the GreenWave, but we call it a “Salt-Free Water Conditioner” not a “salt-free water softener.” We also explain the science a little more in depth:

The GreenWave 2.0 utilizes Filtersorb SP 3 Media by Watch Water. The Filtersorb SP 3 Media utilizes a process called Nucleation Assisted Crystallization or “NAC” for short. As the hard water passes through a pressure vessel (in the upflow configuration) the calcium bicarbonate or Ca (HCO3, is transformed into the aragonite form of calcium carbonate CaCO3 crystals. These crystals are formed through decomposition and crystallization process, forming very stable harmless crystals.

The following equation describes the reaction that occurs inside the pressure vessel when flow over grains of nucleation.

Ca(HCO3)2 → CaCO3 + CO2 + H2O

Most companies do not tell you how much Anti-Scale Media is inside their tanks. However, if you check, you will find out that it is generally about half of what we use. Ours is engineered to be long lasting and more efficient, typically lasting 4-6 years.

TAC NAC Systems

Insofar as I can tell, the US Water Systems Green Wave, Pelican Water's Natursoft, Aquasana's Salt-Free Water Conditioner, Filtersmart, Smartwell, nextScale Stop, Spring well Water, Watts One Flow, Lifesource, and several others all use the TAC or NAC technology. This is time-proven technology that does not soften the water but does provide protection from hard water scaling.

Citric Acid Systems

The second type of salt-free system is the introduction of citric acid into the water stream, which is what NuvoH2O offers. We have used this technology and it is highly effective at preventing scale. We have utilized in streamers and several other food service applications. My problem with this technology is that it lowers the pH of the water, which could potentially create corrosion. I believe they prevent that problem by only injecting a small amount into the water supply. However, that makes it less effective in preventing scale.