Running dry can be destructive to fluid pumps. We have done pumps on fluid containers which were sitting on load cells (the containers, not the pumps). Used the weight reading to stop the pumps before the reservoir would run completely empty. I am not saying such would always be the best way to go about. It did nicely for pumping some fairly aggressive fluids (hard to find suitable sensors, customer wants to limit additional connections to the bare minimum in order to minimize chance of leaks, etc).