reef newbie,
I personally don't use canister filters.
IMO - They tend to need more maintenance than other types of filtration.
The more popular trend in reef keeping is to use Live Rock and a Live Sand, with or without protein skimming.
Canister type filters will trap wastes ( as they are intended to do ) and if not maintained properly, with a strict schedule of replacing/cleaning the filter media, can contribute to higher than desired nitrate levels in your system. Reefers, as well as most hobbyists, want as low of nitrates as possible.
Canister filters thus are normally not the best choice, although I'm sure there are some beautiful reefs out there that utilize them.
Anyone out there using canister filters want to comment ?
Brian