Full disclosure: I didn’t do anything to add extra oxygen except take some water out. The baffles in the back and gas exchange at the surface where it’s kinda choppy are the only way oxygen gets in my tank. Lowering the water level produces tiny bubbles though and this was obviously enough.I have one of those! And a splitter. My only concern is to make sure not to contaminate my fishes qt with coral tank water or vise versa.
I also have a little powerhead with one of those long cylinder heads that have a bunch of holes in it that creates a ton of bubbles.