The hardness of the water is due to the content of calcium and magnesium salts. When determining the water hardness, the sum of all the salts mentioned above is recorded. It is given in mmol/L or in the older, more common designations such as German, English and French degrees of hardness. Water is often assessed in addition to the degrees of hardness mentioned above with expressions such as "soft water", "hard water" etc. Below is a comparison of °d and these general terms:The hardness of the water is often of interest even where no special water laboratory is available. The sensitivity of AQUADUR ® is sufficient for indicative water hardness determinations in companies in the textile industry, in dye works, laundries, water works and boiler houses, in fish breeders, aquarium owners and also in households. AQUADUR ® Sensitive is used for the highly sensitiveMeer tonenMinder tonen