My final design on a venturi for use in the 3DPONICS system. I run two of these on a dual air pump to water about 1 gallon per hour from each line to my hydroponics setup. I increased wall thickness to eliminate air leaks and I adjusted the venturi design to allow for more vacuum and water flow. Short YouTube video on both venturi's in action. http://youtu.be/ZpmO-1WytU8Print standing up, .2mm layer, raft on, 15% infil