Years ago I used to rent a water sofner bottle from a water softner company for $10 a month. Take it in for a new bottle once a month. Now their not too expesive to purchase. Pro chem has them.
Anybody use a slower RO filter like say a 200 gal per day one and fill a tank in your shop then just fill your fresh water tank? Be cheaper then and save a lot of space. I don't have room for a RO setup inside my van.