The Overfill Alarm Stattion, a.k.a Fil-A-Larm System, is designed to be located near the tank fill terminal to notify of a potential overfill condition. It triggers a high level alarm that alerts the filling operator that the tank is filled to its predetermined capacity. The Preferred Fil-A-Larm system is installed in conjunction with underground storage tanks and above ground main storage tanks. It is designed to be located near the tank fill terminal to notify of a potential overfill condition.