Systems and related methods pump fluid through a pump. The pump comprises a pump chamber, which is responsive to applied pressures to convey fluid. The systems and methods place an electrode in electrical conductive contact with fluid in the pump chamber which, in use, is coupled to an electrical source. The electrode generates an electrical field in the pump chamber that varies according volume of fluid in the pump chamber. The systems and methods register variations in the electrical field as fluid is conveyed through the pump chamber.