Chemistry & units
Hardness from calcium and magnesium
Calculate total hardness from measured calcium and magnesium concentrations, as laboratories report them.
Result
Total hardness
290.9mg/l as CaCO₃
Contribution from calcium
249.7mg/l as CaCO₃
Contribution from magnesium
41.2mg/l as CaCO₃
German degrees
16.30°dH
Classification
Hard
Significant scaling on heating elements and in kettles.
Method
Total hardness as CaCO₃ = (2.497 × calcium mg/l) + (4.118 × magnesium mg/l). The factors are the ratios of the molar mass of calcium carbonate to those of calcium and magnesium.