Low-pressure mixing of fluids includes a pumping system having a pump and a fluidic inlet port through which fluid is introduced to the pump. A fluid proportioning system is in fluidic communication with the fluidic inlet port of the pumping system to deliver thereto a fluid stream comprised of multiple different fluids. The fluid proportioning system includes a manifold having a plurality of inlet ports, an outlet port connected by tubing to the fluidic inlet port of the pumping system, and an outlet conduit providing an internal fluidic passageway to the outlet port. Each inlet port is fluidically coupled to a fluid source to receive one of the different fluids and to the outlet conduit to deliver thereto the received fluid for delivery out of the manifold through the outlet port to the fluidic inlet port of the pumping system.