Adele ring. In mathematics, the adele ring (also adelic ring or ring of adeles) is defined in class field theory, a branch of algebraic number theory. It allows one to elegantly describe the Artin reciprocity law. The adele ring is a self-dual topological ring, which is built on a global field.
Real softeners generally last 20+ years EVEN on ludicrously hard water while the service life on a pre-built softener seems to be under 5 years (if you're lucky) on really hard water and lasting longer than that is a rare exception.
The person who sets up the softener takes an educated guess at the capacity of the softener (how many gallons of water it can treat between regenerations) then another guess at how many days it will take for the inhabitants of the home to use that number of gallons. He then sets the timer accordingly. For example, if it seems that the softener can treat 1000 gallons of water between regenerations and that the family will use about 300 gallons of water per day, the softener might be set to regenerate every third day. That allows a little room for error.