POwer/canister filters are generally viewed as something more for freshwater or temporary saltwater use (say, during display at a swap) than for permanant reef use. While there are some people who apparently use them successfully, they're rare on reef aquaria. There're a number of reasons, but basically it comes down to the fact that they can become nitrate factories, and because if they go anoxic during a power failure, which can happen pretty quickly, they can kill your tank when they come back on.
It's safer (and lower-maintenance) to go with a skimmer, biological filtration, and sufficient clean-up crew and other life in your tank, in most cases.