Merck, 1.10025.0001, Total Hardness Test

Method: Colorimetric, with test strips, 4 - >7 - >14 - >21°d, 5 - >9 - >18 - >26°e, 7 - >12 - >25 - >37°f, MQuant® The MQuant® total hardness test strips can be used to measure water hardness. The hardness (total hardness) of a given water is due to its content of salts of the alkaline earth metals calcium, magnesium, strontium, and barium (“hardening constituents”, later compounds only in traces). In the presence of a green indicator the hardness ions Ca²⁺ und Mg²⁺ react with Titriplex® (III) to form a colorless, stable complex. The hardness ions that are present in excess relative to Titriplex® (III) react with the indicator to form a red complex. The reaction zones of the test strip, which are impregnated with differing amounts of Titriplex® (III), thus assume a green to red color, depending on the hardness of the water sample. The hardness is measured semi-quantitatively by visual comparison of the reaction zones with the color rows of a color scale. For other sensitivities and graduations please consider the other MQuant® tests as well as our Reflectoquant® and Spectroquant® portfolio.