The device automatically dumps when the adjustable pivot point on either end of the tank is in the proper position.

When the tank is empty, the bottom is heavy due to the opening in the top of the tank. As the tank fills with water, the center of gravity moves upward toward the pivot point. When the tank is full, the center of gravity is slightly above the pivot point-causing an unstable condition. A piece of foam plastic insulation along the back edge of the discharge opening moves the center of gravity slightly forward of the pivot point when the tank is full. Once the center of gravity is both slightly above and slightly forward of the pivot point, the tank dumps forward. The tank is allowed to rotate in a full circle around the pivot point.

No stops are used to avoid mechanical damage due to sudden stoppage of tank rotation.