Very nice! I like this setup a lot! I was thinking about doing some strawberries and may copy your setup. Question though.. on the end caps where your return lines are connected to the middle, doesnt this allow an inch or so of water to always stay in the bottom pipes or is it hard to tell the slope of the pipe that prevents this?

Yes, there is about an inch in the bottom all the time. There is an adequate air gap above the water line. There is a slight slope in the pipes to help with drainage. I've seen it done with a drain directly from the bottom also. This is a picture from the other side. I'll have to net the berries soon to keep the birds away !