You would use either sponge filters or corner filters (I use one of each in each tank so that if I need to use chemical media, I can).
I am nto sure why these lost so much popularity, but they usually cost from $2-6 each. You put in established gravel in the bottom, then most people put floss on top of that. I use these in my breeding and import tanks in case I have had ot medicate and want to remove the medication with carbon. They are totally air driven, just like sponge filters you just can customize their media more. they are a bit of a pain to clean, but at $2 each, I cope
I do'nt use a central water system, as I import. I cannot risk contaminating one tank with another and use separate nets, hoses, etc for each tank.