The venturi in the tower aquaponics system doesn’t seem to work reliably. I’m guessing that the inner pathway keeps getting blocked, either by artifacts of the printing process, or with gunk pulled in from the water. In any case, I’m going to try a different approach. Specifically, I’m going to put a small pump in the tank, and have that on a timer, periodically flooding the bottles. To do that, I need to connect tubing of various diameters. I poked around on Thingiverse and found this hose barb adapter and manifold (CC BY-SA, by papergeek).
A few tweaks in the Customizer, and I’m able to print essentially any barb I need. Using a 3d printer to print objects to demonstrate 3d printing is one thing, and using a 3d printer to print useful objects for immediate use in a project is something altogether different – something like a miracle.