Vikki, the small low pressure pumps are not meant to be run full power all the time witch it would be with a bypass back to the tank. It is a solenoid vibrating type of pump.(not rotary vane type)
It could be used (with a dash switch ) to prime the system or on a full power blast to keep the fuel bole full.
But I wonder if it would be more of a restriction in the system if turned off.