Abstract: An automatic sensor system for detecting and adjusting a level of contents held within a reservoir is disclosed. The system has a sensor probe having a probe housing with opposing ends, an interior cavity that opens through one housing end, and a constantly open air vent aperture piercing the housing proximate the other housing end, included within the housing are lower and upper level detection contacts that communicate information about the detected level to a circuit that signals for a contents delivery source to send additional contents when needed.