The canisters usually don't provide the surface breaking/agitation that I like and get from the Whispers. I also already have all this filtration on the tank already except for the 404, which I have two of sitting around, so it's not like I'm investing in them new if that's what you are thinking. I already have the PVCs and all my current rock and woodwork is in other tanks (55 discus, 150 african peacocks, 40 community), but I will think about getting more stuff like that. I thought they would like the pipes better, why not?