I don't see a problem with the canister filter as long as you don't use any biological media in it (ceramic rings, bioballs, etc.). That's where you'd likely run into nitrate problems. Running a small amount of carbon or other nitrate or phosphate reducing media would be good if needed. You probably already know, but on a small tank, weekly or bi-weekly small water changes will probably get you the best results. A lot depends on if you're going to keep coral or not but it sounds like you are if you're spending money on T5s.