Canister filter waste

[got bait?]

I recently purchased a 100gal tank used from neighbor. It came with two 6mos old Eheim Professional canisters 1 wet/dry 1 regular. I am probably going with a sump/fuge, so what can I do with these canisters. Not enough water volume to just add on for more mass. I would like to use these instead of a sump if it would work. I've heard so much about excess NO2 and NO3, in the media though. I plan on a no fish reef.
Any suggestions?

 

[fishfreek]

Take the media out and use them to move water. But i dont think you like that idea. Aside from water movement unless you want to be doing weekly filter cleaning to keep the nitrates down I woulnt use them for anything else.