Here is my idea, take 2 canister filters; let's say, 2 XP3 filters. Instead of having 2 intakes and to outtakes in the tank, how about linking the 2 together?? You would start with one filter and run the intake from the filter to the tank. Then cut a small section of the hose and connect the outtake of the first filter to the intake of the 2nd filter the run the outtake of the 2nd to the tank. You would want to be able to turn them on the same time, so put them on a power strip or extension cord. The only problem I might see is that if one were to fail, the the other would be pushed to hard to compensate and prolly burnout quickly. But, it might make an interesting experiment for someone. Just an idea I cooked up!! Might be even better than a sump filter.