Course Salt is sodium chloride (e.g bog standard salt) with no iodine added sold for use in helping to soften water in dishwashers. It is, a granular salt, with grains larger than table salt, the fine particulars of a salt ground for table use might clog the softener mechanism in dishwashers, or interfere with the process so that you end up hardening the water.The soft itself doesn’t soften the water. The salt doesn’t even get in to where the dishes are. What it is used for is to “activate”, or “reset” the mechanical device in the machine that does the water softening. The device is a basket-like contraption that contains resin in small yellow balls.