Good idea but it would be a poor chocie for filtration and if did work would need cleaning way to often. Surface area is limited and packing will be to tight for good water movement over the filtration. I would not think that a sufficient flow would be achieved either because the air is going to have a hard time snaking up that matrix of fliter floss, sponge, and biomax. The order of filtration is also strange. Filter floss is more for water polishing and should be later in the filtration as larger particles have been removed. You would be better off using the UGF
tubing for the center column of a simple sponge filter and achieve much better results (not as compact as your design).