Using a canister filter on a fish only salt water set-up

[FishyFishy!]

I have successfully kept numerous tanks running on a canister AND a skimmer. Works just fine. I currently have a 39 gallon bowfront running on a new Fluval 406 with carbon, phosban, and 2 media trays with live rock rubble. Tank has flourished. Also running a Hydor slim skim on it.

That being said, just like gobytron mentioned, as long as the user is diligent enough with regular water changes, a skimmer isn't manditory. If he is a beginner, I would recommend a skimmer.