A sensor for measuring a level of a conductive liquid, is provided. The sensor includes at least two electrodes that can be positioned in a holding tank so as to be partially submerged in the conductive liquid, sensor leads coupled to the at least two electrodes, and circuitry and a controller for determining the properties of the electrolyte, the circuitry being coupled to the at least two electrodes via the sensor leads, and the controller being coupled to the circuitry. The sensor may be used as an electrolyte level sensor in a flow battery system.