I took at 30 gallon tank and inserted a 10 gallon tank down inside of it. I then raised my skimmer up about 6" off the bottom of the 10 gallon. I was curious if anyone thought it would be a good idea for a refugium inside the 10 gallon tank also. The water would fall from the overflow into LR rubble with live sand and algae, then the water would be pumped through the skimmer. I don't have the room for it on the outside of the 10 gallon. My tank looks so much better without all that equipment packed inside.