It depends on what you have... If it is a water softener, then yes... calcium and magnesium and other minerals are attracted to the salt (Sodium Carbonate), and Sodium will be released into the water.
I doubt you have a descaler or a magnetic device... Here's a link.
http://home.howstuffworks.com/question99.htm
Fair use excerpt:
Descaling offers an alternative to water softening. Whereas a water softener removes the problem (minerals in the water), a descaler addresses the damage caused by the problem (scale buildup). You will sometimes see ads for "salt-free water softeners," which are actually descalers, or for magnetic water softeners, which remain unproven and don't change the chemical composition of water, so buyer beware [source: Powell].