AquaFX The leaders in reverse osmosis. AquaFX 100 GPD Piggyback Membrane Add On Kit Increases Product Water Output Includes All Components for Install Comes with a AquaFX 100 GPD Membrane Comes with the 100 GPD Flow Restrictor 1 AquaFX 100 Gallon Per Day TFC Membrane 2 Mounting Clips 1 Standard Membrane Housing Additional Tubing 3 Tee&#039;s Running your waste water (concentrate) into the AquaFX Piggyback will provide a second pass to create purified water from the waste stream reducing the amount of water used.