Some conductivity meters do not compensate for factors such as temperature, and will therefore need calibrating. Unlike pH meters, only one reference point is needed to calibrate conductivity meters. They are tested against a solution of known conductivity, called a ‘conductivity standard’.

The higher the conductivity levels are, the harder it is to measure them accurately. Therefore conductivity standards are usually set to around C.F. 28, which is the maximum level for general hydroponic gardening.