A fluid supply system adapted for vacuum and pressure cycling of fluid, including a transfer vessel adapted to supply a process canister with fluid drawn from a bulk canister under a vacuum, wherein delivery of fluid from the transfer vessel to the process canister is accomplished with positive pressure. A method is also disclosed of delivering fluid, including drawing fluid under vacuum from a bulk canister and pressurizing the transfer vessel to effect dispensing of the fluid into a process canister for delivery to a location of use.