I built a self watering greenhouse a few months ago. the self watering system has worked OK for the most part... But.. it does develop some nasty green slime in the water, due to lack of oxygen and circulation. My plan is sometime this winter I'm going to convert the still water basins to ebb and flow hydroponic. I only have about 2 amps 12 volts of solar available. So running an aerator with a stone and a pump is out of the equation. Why not kill 2 birds by having the pump do both? I settled on a 12 volt 325 GPH pump that draws around 2.5 amps. I want to keep the head pressure and restrictions to a minimum. So I designed the 4 venturi mini tower aeration system. Based on Bernoulli’s Principal, which states that as the speed of a fluid increases, the pressure within it decreases.
1-30-14, I have an actual system up and running using the mini tower, I made a few changes to the project based on my observations to maximize aeration. My circulating pump, in the system, is about 150 gph at a 7' head.
Step 1: Make the venturi's
I started out thinking I could make these with brass bar stock and copper pipe fittings. Big fail on that. I had loads of trouble trying to bore a taper in the brass stock and only seceded in burning up a not so expensive drill. So a trip to Tap Plastics got me a 2' piece of 1" diameter Delrin plastic bar stock I cut four 4" pieces to start.