Ecozone Magnoloo, the Anti-Limescale Eco Friendly & Chemical Free Toilet Descaler. Simply drop the Magnoloo into the cistern, it will sit at the bottom of the cistern & treat the water magnetically so that the calcium carbonate does not form a hard limescale, & instead flows out of the toilet with the water, as well as helping to prevent or eliminate stains & limescale. Each Magnoloo magnet is guaranteed for 5 years, so this great product can save you money also!