What is the main difference to softening with ion exchanger units?
Ion exchange resins remove Ca and Mg ions from water and replace these with sodium (or potassium) ions. Softening units require water for backwashing and common salt for regeneration (as an example: in order to regenerate 100 liters of softening resin, up to 25 kg of salt per regeneration cycle is required). The increased sodium content of the water is a concern to more and more government regulators from two perspectives. First, drinking water with elevated levels of sodium is produced. Typically a Reverse Osmosis system is sold to take the salt back out of the drinking water only supply, but high sodium water still comes out of all other faucets and taps in the home. In addition, the high concentration of saline brine dumped into the sewer systems make reuse of the water for irrigation purposes more difficult. Many septic tank system warranties are voided if water softeners are used due to the brine discharge. Water for backwashing and the salt ($200 to $400 per year to purchase salt
