Supermax (short for: super-maximum security) is the name used to describe control-unit prisons, or units within prisons, which represent the most secure levels of custody in the prison systems of certain countries.
Consumer Complaints and Reviews. Outrageously expensive for services not provided: $690 - the cost to purchase your own, high-quality softener and RO filtration plus 1 year of filters and salt. $5,770 - the cost of a 3-year contract with Culligan to rent their basic softener and RO filtration with service.
Shopping for a water softener: 1  Salt-based units need to have the salt replenished on a regular basis, usually at a cost of anywhere from $2-$15 a month depending on the cost of the salt ($3-$8 per 40-pound bag) and the amount of salt used by your system. The size of the water softener will depend on the amount of water to be softened (and some systems use more than one tank), but many water softeners are anywhere from 3-1/2 to 5-1/2 feet high and 12-26 inches across.