I have an Aqua Clear 50 set up. It's been up and running since August of last year. In it I have Biomax in a bag, and a sponge with some good BB. I also have an Aqua Clear 70. Just the filter box, intake tube and the impeller. I have some extra sponge kicking around, too. I am wondering if I could place the sponge from the 50 into the 70 filter box, and cut a piece of new sponge and wedge it in there. Also, use the 50's bag of biomax for the 70. Plus, I'll get some Purigen. The motors for most of the aquaclears are the same. I can just add the 70's impeller to the motor that I used on the 50. Does that sound like it would work? Thoughts?