I am not familiar with the filter you are referring to. However, filters will remove a certain amount of waste and different filters would perform better than others. However, I have found over the years that the only way to keep an Oscar tank clear of crap is by using elbow grease. Anyone who has kept the Oscars for more than a few days will know how big their turds are. These guys crap like elephants. Waste that large is going to lie in the tank, the only way to get it out is with vacuuming.
I always tell people that if they want to keep fish that don't require much maintenance, get yourself a small tank with a few tetras or guppies. If you're going to keep Oscars, be prepared to get your hands dirty.