If the tank is a cycled tank, then you might only need to put in a small powerhead for circulation, as the gravel should be enough, unless you have lots of fish. Even an air wand will provide circulation as well. How big is the tank and how many fish? And how long has the tank been running?, And as FishyFanatic said, put the media in a filter bag or a new pantyhose sock or something, and keep it in the tank.
55G Filstar XP3 - 16" Fire Eel
75G Medium Planted - Filstar XP3 Low Light - Established Feb 2006