Looks great.
I've been following your progress with it on RC. How is the testing going and did you get the problem you were having with the water flow and levels worked out?
I'm in the middle of designing and building one myself. I'm trying to decide what design to use. Can't decide if I should go with the design with the return holes around the middle injection tube and the 2 90 elbows or the design with the walled off floor in the box with the inner tube coming up through it.
I am only using a single beckett, so, the direct injection using the 2 elbows ( like yours) may work better.
I'm thinking of making the inner injection tube removable for easier cleaning also.