Spectroquant® Residual Hardness Photometric Test [25 Tests]

Definition
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”). Since strontium and barium are generally present in waters only in traces, the hardness is defined as the content in a water of calcium ions, Ca2+, and magnesium ions, Mg2+ (“hardness ions”).
The conventional procedure is to relate the statement of the water hardness only to calcium, in other words to express also the content of magnesium ions as calcium content.
The units for the water hardness relate to calcium or its compounds CaO (1 °d =^ 10 mg/l CaO)

or CaCO3 (1 °e =^ 14.25 mg/l CaCO3; 1 °f =^10 mg/l CaCO3), with the magnesium content being expressed as calcium content and included in the calculation accordingly