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.