Anybody tried a gravity feed set-up for circulation?

[MitchM]

Oh yeah...bubbles... In my tanks at home I'm using the plastic bag baffle set-up, and it works like a charm. However, this tank set-up is for the office (so no special permission required, Tony ), so it's got to be attractive and quiet.
I've always wanted a surge tank, but the upstairs tank will be around 300 gallons, and to get a 10X turnover, I would have to have a 50g tank midway filling/emptying every 10 minutes, plus allow for enough empty space in the lower tank to handle the 50 gallon surge.
Maybe the Herbie set-up with a safety overflow as well as a smaller surge would work?
Any suggestions on pipe sizing? I would like to have as few as possible.
I've got to have this figured out by the end of the month because I'm re-doing the basement office then.
Thanks guys!

Mitch

..and thanks for the offer Tony. I'll give you a call.