Depending on what you plan to put in this tank you might need a filter.
If you are putting in a live sand bed with liverock you will not need a filter for filtration purposes, The LR
, Sand bed & Protein skimmer will filter your tank. If you are not putting in LR
& Live sand bed you will need a filter the type is up to you Cannister or hang on style. I am currently using both styles IMO
I would go with the cannister style a little harder to maintain but does a better job filtering the tank and also has a spray bar to add in water movement. If at all possible I would add a sump setup and place your hardware IE: Heater, protien skimmer, etc. This could also be where you can place your Foam pads and carbon when needed. Until you are sure of what and how you are going to setup this tank filtration methods will vary. Hope this helps if not feel free to contact myself or other members. Good luck