[Delphinus]

I've seen some "up-flow" reactors and boy is it nice to see the entire media bed charged up like that, almost like a fluidized sand filter. I totally agree that an upwards flow idea has merit.

I've thought about changing the flow direction on this reactor design to see what would happen. I suppose, for one thing, one might not need the recirc line anymore (except that bubbles may still accumulate above the pump intake so I guess the recirc line would still have a place). In the end I don't think I could make the "gravity feed" arrangement work in that configuration, so ultimately decided against it for this time around.

Hmmm, maybe the answer is a second recirc line is called for? One at the top of the top chamber and one somewhere in the bottom chamber...