Water hardness is caused almost entirely by calcium and magnesium ion. Other di- and trivalent metals have a similar effect, but usually are not present in high enough concentration in potable waters to cause problems. Hardness increases soap consumption in laundries and causes scale in boilers. With the Model HA-71A test kit, simply count the number of drops required to change the solution color to determine hardness concentration. Utilizing drop count titration, this kit provides dual ranges and contains approximately 100 tests.
|Drop count titration/
|Number of tests
|Hardness, total – As CaCO₃
|Drop Count Titration
|1 – 20 mg/L & 17 – 342 mg/L CaCO₃