Hallo, just to "mention" ... these water softeners are ion exchangers means, they have a very high porosity, giving a real big inner surface. If not regenerated frequently, where the regeneration firstly is the regeneration itself, but secondly also some sort of cleaning, removing organics "sticking" in the resin pores. Especially when not using too much water bio film growing starts very quickly. First of all this is not hygenic and second, the biofilm blocks / isolates the functional groups of the resin from being regenerated. This means the resin loses capacity. Ion exchange resins also should not be fully loaded before regeneration to achieve a longer lifetime. So, the salt usage optimization should be in the way to have intervals frequent enough to prevent from hygienic problems and these regenerations then should be salt dosing optimised.