I think a 15gallon high is the best I can do. I don't have enough space because of the co2 tank, reactor, sump, and reservoir. If I go with the 15g then I have to turn my sump pump sideways and put an elbow before the input. I bought a filter sock from marinedepot.com that will allow me to use the 1 foot square wet/dry space as a fuge. I think something is better than nothing. If it doesn't do enough then I will go with the 15g.