[mbunabum]

Best answer I can give you on a canister is their superb bio filtration capabilities. I generally use multiple filters on my tanks as you can see in my sig... but the hob's are typically for mechanical and occasionally chemical through addition of carbon if required. I use sponge as a prefilter then ceramic rings and seachem matrix in all my filters...including the hob's... but the canisters have multiple trays for holding large amounts of rings and matrix for excellent bio filtration. I feel this combination has worked well for me.