I have a 55 that was running for 3 years as a fish only then I went to a reef setup about a year ago. I have a hard time with nitrates so I decided to set up a 10 gallon refugium under the tank. I too have an oak stand that is divided. the 10 gal
tank sits perfectly underneath (once you figure it out). I have a 600 GPH
spill box (Ebay) and made the dividers out of 1/8 plexiglass. works very well. I have chaeto in the sump with live sand and rock. so I know it can be done and not cost a fortune. 10 gal
. is a little small for the application, but as they say, the more natural filtration the better, and this is really an extention of the main tanks filtration.