I have been scouring Craigslist for a bigger aquarium. I currently have a 30 but would like to add an additional 72 or perhaps 90. Many if not most of the ones on C-list are/were using a canister filter. I would like to hear the pros and cons of using one over the other. I guess I thought a canister filter would be nothing more than a glorified HOB filter unless one used strictly to house carbon and cleaned the filter weekly. Thoughts?