In the salt-free process, minerals are retained in the water, but their form is changed so they will not adhere to surfaces. “Salt-free” water softeners are actually not softeners, they are “water conditioners”.
Despite having “water softener” right in the name, salt-free water softeners aren’t actually water softeners and don’t give you soft water. They’re actually just water conditioners, and they do nothing to reduce water hardness. Water hardness results from excess mineral content in the water, like calcium and magnesium. A salt-based water softener removes those minerals, thus lowering the hardness and creating softer water. On the other hand, a salt-free system works by crystallizing calcium, but not removing it.
Water is processed through catalytic media using a physical process called Template Assisted Crystallization (TAC). What happens is the hardness minerals are converted to a hardness crystal that is not able to bind to surfaces. This is actually water conditioning, not softening. A water test would show this result: before treatment 10 grains/gallon, result post/treatment 10 grains/gallon. Again, the hardness is still there… just changed it so it won’t adhere to surfaces.
There is no electrical valve needed on a salt-free system because the system works as a conditioner and never captures anything, therefore, eliminating the need to purge any minerals. Salt-Free Water Conditioners create hardness crystals but leave minerals present in the water. The crystals won’t adhere to surfaces so you will only see a reduction in scale build-up, not an elimination. Homeowners should not be expecting the same results as salt-based technology.
Since a salt-free system crystallizes the calcium in your water, the calcium won’t be able to adhere to the insides of your pipes. That reduces scale buildup in your plumbing, which is the only benefit that a salt-free system offers. This falls far short of the many benefits of a real water softener. Salt-based systems will outperform salt-free for overall water softening. The best way to soften water is with a salt-based water softener.