The Calcium test gives an indication of the level of soluble Calcium ions present in the mud.
Such ions are considered detrimental since, under conditions of high pH (>11.5), they may render polymer treatments for viscosity and fluid loss less effective.
High levels of Calcium will also flocculate Bentonite.
The total hardness should be controlled below 400 mg/L and must not be allowed to rise above 600 mg/L.
Calculations and Reporting
Calcium Hardness is usually expressed in mg/l CaCo3.
Sources of Error
Can be difficult to see the end point of the test.
Calcium hardness can also be reported as mg/L CaCO3. Multiply this value by 2.5 to get the required value.