A shut-off valve includes a float and a negative G control component. The float is configured to occlude a tank outlet at a first fluid level and 1 G and unocclude the tank outlet at a second fluid level and 1 G. The negative G control component is operatively connected to the float to limit fluid, e.g. liquid or gas, communication between a tank outlet and an ejector pump during negative G events. An ecology fuel return system includes a tank, an ejector pump, a float, and a negative G control component, as described above. The tank has an inlet and an outlet. The inlet is configured to be in fluid communication with components of an engine. The ejector pump is in fluid communication with the tank outlet and is configured to pump fuel from the tank to a fuel pump inlet of an engine.

A device for preventing the overflow of a fluid reservoir, having a first tubular body with a hole through the interior and exterior surfaces at one end, a second tubular body disposed within the first body such that a portion of the interior surface of the first body and the exterior surface of the second body define an air channel, and a floatation device. The position of the tubular bodies relative to one another determine whether air from a fluid reservoir may exit the reservoir via the hole in the end of the first body. The flotation device is connected to an end of the second body and floats in the fluid reservoir wherein movement of the second body relative to the first body is caused by a change in the water level, such that the air channel is opened or closed by the position of the floatation device.

A shut-off valve includes a float and a negative G control component. The float is configured to occlude a tank outlet at a first fluid level and 1 G and unocclude the tank outlet at a second fluid level and 1 G. The negative G control component is operatively connected to the float to limit fluid, e.g. liquid or gas, communication between a tank outlet and an ejector pump during negative G events. An ecology fuel return system includes a tank, an ejector pump, a float, and a negative G control component, as described above. The tank has an inlet and an outlet. The inlet is configured to be in fluid communication with components of an engine. The ejector pump is in fluid communication with the tank outlet and is configured to pump fuel from the tank to a fuel pump inlet of an engine.