actually, I run 2 tanks in the same fashion, with the canister on the table next to the tank. I use Eheim cans, 2215 and 2217, and they will work this way. It is harder to get them primed, and you have to shut in and out flow valves before performing waterchanges to avoid lowering the water level in the canister. For priming, I usually have an extra eheim hose, with the correct disconnect end on one end, so I can attach it to the return hose on the filter, and start the siphon into a bucket. Then I reattach the outflow to the tank and open the valve back up.