Nice build but the prob u will see is the root structures will grow down and entangle. So You might need a way to 'pull' a grow pot and 'trim' excess rooting. Also the cross section of the guttering is too small....the roots will potentially bundle up and choke off the 'rain' flow.
You need about 1' diameter.
Also if this thing is in the weather, the normal rain will get into the grow pots and overflow your tank and mess up your E.C.
As it happens I designed an built a complete control system 12VDC, fully Photovoltaic based on a 55 Gallon tank from Rotoplastics, growing plants on the sides and top, with an optional 'trellis' box for heavy fruiting.
Super energy efficient. The built in 7Ah 12VDC batt. can run the system for 3 days with no sunlight at all.
BTW the control system , seen in the 4x2" white box in the pic, monitors E.C., Ph, root moisture, timing protocols, Battery voltage, runs LED lighting and is programmable for 'weed' growth optimizations and is thus suitable for sales in Colorado.

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The controller directly runs a 12VDC pump cycle and monitors the pump for proper function to alert you if the pump stalls or fails. The system flashes an LED heartbeat once per minute to indicate all is functioning well.
CARIRI wants to seed fund the commercial development but, I am a bit busy right now to do that.
http://www.ipsnews.net/2014/02/indoor-f ... te-change/