Calgon 4in1 Tabs x 15 (Case of 7)Calgon 4in1 Tabs x 15 Calgon 4in1 water softener tablets are fast acting to boost efficiency for your washing machine by removing limescale and helping your washing machine to live longer. They are suitable to use alongside your washing liquid, washing capsules and washing powder. Simply add one Calgon 4in1 tablet to each wash into the detergent section of your washing machine with your laundry in addition to your usual laundry detergent for: 1.