From my experience I've found that easiest thing is to have a barren tank, not the prettiest thing, but I think the best way to go for lazy people and instead use like two power filters www.cichlidfish.com/oscars/OscarTanksetup.shtml
Joe what is a barren tank? i have the aquaclear 500 and the undergravel filter going now.i was considering taking the undergravel out.i have never heard of a barren tank, please explain.
Problem with gravel in oscar tank is that their "waste" is BIG and ugly and will break apart into little chunks and get real comfortable in your gravel, unless you got filters creating a tropical hurricane in your tank.
Take it from me, I have 100 lbs of gravel in my tank covering my undergravel filter. It's a pain in the everything!!! It's 2 in. deep in the front and 4 in. deep in the rear, and a back killer to clean! It looks really good, but I hate cleaning it!
An Oscar's tendency to mow around in the gravel, is generally accepted that an undergravel filter will not work well. When the Oscar digs far enough down to the filter's plate, then the water bypasses the gravel and you lose much of the biological filtration that a UGF depends on.