When I was looking at new softener solutions a few years ago, there WAS a service from Culligan whereas, instead of renting their whole resin tank and brine tank system, you could have them come out every few weeks or a month, to fully swap out a pre-charged resin tank. They take your depleted one away, and replace it.
So salt for the user to buy or maintain.
So salt for the user to buy or maintain.