With 50% more effectiveness versus MAXTRA+ Universal in reducing limescale build-up, the MAXTRA+ Limescale Filter is formulated to suit areas with moderate to hard water levels. Australian household mains water is strictly controlled, however limescale build-up is a prevalent issue for those living in moderate to hard water areas. Hard water refers to water which contains a high mineral count and occurs when water passes through soft rocks like chalk or limestone and picking up the minerals from them. Whilst this is not harmful to our health, hard water often results in the unpleasant smell, taste and mouthfeel when drinking.