Level switches utilizing the conductivity principle are applicable to liquids with conductivity higher than 10 μS/cm. For detecting the level, probes are immersed into the tank. These probes, and in some cases the conductive tank wall, serve as contacts of an electric circuit. Multiple probes of differing lengths can be extended into the tank. Each probe length should extend to the level to be detected. As the tank fills or empties, electrical conductivity between the tank wall (or the reference probe) and the level measurement probes in the tank will change, due to the liquid media creating or removing a conductive path between the monitored points. The established connections will be detected and will activate a relay providing an output signal.