An apparatus for improving the service life of a submersible probe residing in a tank includes a liquid level detector adapted to detect when a liquid in the tank rises to a first level. The first level is above the probe. A controller is coupled to the liquid level detector. The controller is configured to increase at least one of a voltage and a current applied to the probe responsive to the liquid being detected at the first level. The controller is configured to reduce an electrical potential field produced by the probe responsive to the liquid falling below a second level, thereby extending the service life of the probe by reducing the accumulation of foreign matter on the probe when the pump is not activated.