I use Salt-Away. Usually get it at Boaters' World.
The anodes are the most important thing; corrosion is a bigger problem than the salt itself.
Don't know about anyone else, but I do...run it on flush first until hot (stats open), then switch to soap and shut off when it starts to lose the blue color. In fact I'm going to town Tuesday for another gallon..doubles or more the years I get out my manifolds on my 350 I/0, and the outboards get it too after a good fresh water flush when they get yanked out of the salty corrosive waterThanks a million ezeeke. Do you use Salt-Away after each use?