The mineral agent calcium is present in water at variable concentrations and is expressed in °dH (German hardness degree). Calcium is not visible, but it forms deposits depending on the degree of hardness when heated. These deposits damage household appliances such as automatic coffee machines, coffee makers, kettles, and teapots. The Soft Filtered Water Extra cartridge from BWT is specifically designed for treating water with a very high hardness level (over 15° dH). The reliable reduction of water hardness protects household appliances from limescale deposits. The specially designed filter also reduces heavy metals (such as lead and copper) as well as substances that disrupt odor and taste, such as chlorine. This makes tap water noticeably softer for unlimited enjoyment. Protection of household appliances. Hard water leaves unsightly limescale deposits in household appliances like kettles or coffee machines. This not only leads to poorer heat transfer and thus higher energy consumption but also affects the functioning of appliances and reduces their lifespan. Additionally, limescale deposits promote the growth of microorganisms such as bacteria.