Wow! A lot can change when a small-scale prototype fails.
My daughter's rather whimsical design idea for configuring the vertical farm, and having a pump run off of gravity and rotation of the growing system was a non-starter after trying to just get part of it assembled. So... scrapping that, and going with a much simpler design. The growing system will be a "stair-stepped" series of PVC pipes with conventional top fed hydroponics. However... I hate the idea of using power on the recirculation of the nutrients. So, I'm going to build a small hydraulic ram pump today. I believe I can capture the waste water that normally would just spill off, and feed it through a "Wye" connector, and use the venturi effect to be able to effectively siphon the water (in my case the nutrients) that would normally be discarded. If this works as I think it will, the recirculation of the nutrients will occur without any electrical power used, other than to periodically open the valve for releasing the nutrients.
If that doesn't work, I'll go with an "air-lift" pumping system, using a low voltage (12V), low wattage air pump so that the solution can be aerated at the same time that it is being recirculated.
With all that said, I'm going to have a cigar, feed my horses and then head off to Home Depot to get more PVC pipe, a couple of check valves and see if I can't make this work .
