ive been looking into diy refugiums out of HOB filters for my 24 gallon flat back hex. would i be able to make one out of an emporer 400 filter, leaving the one half to filter debri and the other half as the fuge? or should i make it a completely seperate unit? i have a penguin 170 that im not using anymore thats sitting under my 75 gallon taking up space. would this be a possibility also? id rather not make a seperate unit because the 400 already takes up so much space on the back of my tank. i think i tried to fit both the 400 an the 170 but there wasnt enough room. i would rather steer away from using a smaller tank with power heads and all the works for mechanical reasons. i also dont have tht much room to work behind my tank. inputs?