Calgon 4-in-1 water softener tablets are fast acting to boost efficiency for your washing machine by preventing limescale build-up and helping your washing machine to live longer. It's suitable to use alongside your washing liquid, washing capsules and washing powder. Simply add one Calgon 4-in-1 tablet to each wash into the detergent section of your washing machine with your laundry in addition to your usual laundry detergent for limescale prevention, removal of dirt and residue as well as odour elimination.