An apparatus and associated process for constructing a conductivity probe are disclosed. The conductivity probe includes at least two magnetic circuits in toroidal shape. Each of these “toroids” includes a ferrite core around which is wrapped a conductive wire (i.e., coil winding). To construct the conductivity probe, a toroid keeper having an upper annulus and a lower annulus separated by a spacer is provided. One of the two toroids is set on the upper annulus and the other toroid is set on the lower annulus. Connection leads extending from the coil wrappings of the toroids are routed from the keeper through wiring channels build into an elongated neck coupled to the keeper. The connection leads terminate at the distal end of the elongated neck relative to the keeper for connection to a controller.