-Planning your process in starting your tank (eg. Salt,Sand,Liverocks,ANN Cycle,Adding Fishes,Adding Corals)
-in my honest opinion..a sump tank will be better and save u time from upgrading as u continue in the hobby..
there are many advantage of using a sump tank as a filtration method..
(eg. Refugium Area,Equipments Storage Space......)
-an overflow system is impt if u r using a sump tank or runing pipes/hoses to other equipments