still looking into getting a new filter. mine is getting extra loud i think some sand got sucked up. :evil: so ive been searching around an such for a loing time now on canister filters and ive came across many people who believe 2 smaller canister filters is better then one large one. i have a lightly planted tank at the moment with no large fish. its a 55 gallon with 8 BA tetras, 2 blood fin tetras, 3 black skirts, 2 peppered cories (one died last weekend :-( ) 2 black kuhlis, and 2 angelfish. my filter i have now works good enough to keep my water clear n clean. so on a tank this size would two smaller canisters be overkill an make sense to get one nice large one that will turn my water over 5 times or so an hour?
One eheim 2217 would be what I would choose and is what I am running on 55 gal with four pleco's,approx three dozen fancy guppies,and maybe a couple hundred Cherry shrimp.
The eheim 2217, comes with all media included and is dead silent in operation.Rated at 267 GPH.
I was using two Eheim 2217's on 80 gal but it proved too much movement for the small tetra's ,Pearl gourami,Shrimp's so I bought Rena XP3 for the 80 gal,moved one of the eheim's to the 55 gal to replace Aquaclear110,and now have a spare Eheim 2217 so that when one is dirty and need's cleaning,,I can just swap it out for the spare one.(no rush to clean the dirty one)
Is something to be said for two canister's on larger tank's ,rotate cleaning,extra flow,circulation ,but one eheim 2217 is working well for me on 55 gal.
Keep in mind that advertised flow rates for most filter's can be reduced by approx 25 to 35 %, once they are loaded with media Pad's, sponges,foam,biological media.
Advertised flow is often minus the Media that we place in them.
If you are planning on larger tank,,then I might consider two canister's, but the one eheim 2217 would in my view be just right for 55 gal.