I have a 20 gallon QT. It has only 15 watt NO lighting. I have a Eheim Classic cannister filter. There is a very small amount of crushed coral (which I would have to remove if I were to use medications). For hiding places, it has some PVC pipe and some nontoxic aquarium decorations my wife bought for the kids to look at. That's about all.
BTW, I just saw this was your first post. Welcome to the Boards!