What will cause my float bowls to go dry

I had the problem on Gladys where the fuel in the line between the carburetor and pump would drain back through the fuel pump towards the tank. I solved it way back then with a Dorman one way check valve. I've since replaced that fuel pump and redone some of the fuel system forward of the pump. I'm getting ready to add a high flow fuel pump and return line with a return style filter before long.