Just finished my Quik'n'Dri upflow tower.
It is a 6" PVC pipe about 5 feet long with reducers on each end. I pump up through the Quik'n'Dri inside the tower, oil comes out the top and then goes through a particle filter before looping through.
I will post pics and more details in the near future.
Has anyone else done a pressurized upflow like this? If so please chime in, maybe we can learn from each others mistakes.