Step 3: design the vortex chamber
look below at the schematic I made. You'll notice there are TWO types of vortex chambers, the Archimedes screw, and the opposing jet (this is what I used, but I plan to test the Archimedes screw soon)
So, depending on which one you want to build, you may, or may not need the T fitting for the air lines.
the Archimedes screw does NOT need the T fitting. but needs 1/4" air lines
the opposing jet design DOES. can use either 1/4 or 1/8 lines
now, the archimedes screw all that's different about it, is that you need to drill ONE hole instead of two, and you must design the one spin spiral (does not need to be perfect, just has to be smooth)
we'll discuss the two opposing jet design. HOWEVER, please note, the archimedes screw must fit into the 3/4" pipe. Also note that the "two piece washer sandwich" below, is what both of them will be. the indentations are JUST so that the PVC pipes have somewhere to slot into. They're glued in place then screwed together so the washer is sandwiched between them.