A venturi mixer pulls the coolant concentrate via pressure created by the water source, then mixes it with the water in the inner chamber. When attaching a garden hose to the outlet of a venturi mixer, the water pressure is instead used to push the column of fluid through the hose, resulting in a loss of coolant concentration, or none at all. The Zebra Proportioning Pump is required for long distance coolant mix delivery such as through a garden hose or even through hard conduit. It works by a process called positive displacement whereby a piston is moved by the water pressure. Each time the piston moves, it draws a given amount of coolant concentrate which is then mixed with the water through the hose or conduit. Therefore, it does not lose its ability to pull concentrate even though it is also pushing the column of fluid. The Zebra Proportioning Pump will be able to mix and deliver the coolant mix up to 800 feet laterally, and up to 20 feet vertically! We recommend utilizing a check valve on the outlet side for any vertical installation so the column of fluid does not create back pressure to the pump.