So I came across an Eheim 2017 with no impeller. I'm getting the ol' lfs to order me a replacement impeller so I can get it running for me. I'm planning on replacing my HOT Magnum with the canister and trying to run it's outputs into my Marineland Bio-Wheel 350. I'm trying to conserve energy, and save on the power bill, so i'm planning on killing the power to bio-wheel and splitting the output from the canister in two ways, one tube going to each compartment of the HOB. I plan to do this because I want the beneficial bacteria from the bio-wheels, but I want to run less energy.

I know that by turning off the power to the bio-wheel I will be cutting down the gpm, but would this be enough filtration for a 55?

haven't got a clue, never known anyone do this before. However, if you do, I would've thought that you would actually cut down the efficiency of the canister filter quite dramatically.

I can't see any point either, the flow rate to the canister would match the internal space for media for that amount of flow, giving the canister a larger volume of media isn't going to achieve much cos the flow rate isn't going to be right, so your defeating the object. that's why companies make pumps of different size to match the canister size. if you did want to do as you say and divert the flow I through the other unit anyway i would a buy one of these. link below

cut a hole fit that kit, and then connect the canister outlet to the hose of the butt link. hope that makes sense and is of help.