[koffee]

I have the return in the middle. However, instead of sending the overflow into the fuge, I have a small pump in the return chamber that feeds the fuge. It means another pump to maintain, but easy to control the flow rate. The fuge dumps back in to the return chamber, which means some of the water just cycles back into the fuge. But it all mixes around, so I guess it is OK.

If possible, I think you would be better off with a longer tank, though. It will be hard to squeeze everything in 30". One mistake I made with mine is that the return chamber is narrow, and that's where evaporation really hits. The narrower this chamber is, the quicker your pump can run dry.

I don't like the designs that put the fuge in the middle because I agree with slower flow through the fuge. Ultimately, if/when I move to a bigger tank, I will go with an isolated fuge above the DT that just gravity feeds into it. AFAIK, that's the best method. At that point, I'll use bulkheads and external pumps too.