I built this stand for a 60"+ custom tank I don't have yet. Felix the Oscar lives in a $55 petco tank.
Felix gets 100+ gals of fresh water every week.
I'm showing the plumbing without all the fake ivy on it, in this old photo. (Cloudy from bubbles, right after I moved his tank back to the foyer.)
This wasn't enough flow. I had to enlarge the pump, the weir and the siphon. He's getting over 300 gph now.

He has since received a 6" Bacto-surge filter, as well as 2 more and extra bio-rings, in the sump. I also took out the big heater and put two small ones in the sump.
At nearly 11" long in a 12"x48" tank, Felix the Oscar is quite healthy, but he gets lots of effort and water changes + frequent siphoning
and it is a challenge. I could not do this, considering that I run (and constantly experiment with) 7 other tanks, if I were not retired and healthy. So for now I change his water 3x or 4x a week, and he remains spotless and hungry if slightly lean for an Oscar.
I would never recommend this to anyone unless you like constant water changes.