It kinda looks like the tetra internal filters. What I did was, I squished some of the foam where the water pours out and put a large silk plant infront of it to brea up the outflow even more.
I usually dont bother with the cartridges and just stuff the thing with the foam but anyways, i squeeze an extra peiece in where the lip is (where the water flows out). Since the foam is pretty flexiable, you can squeeze it into small spaces
It unfortunately is closed on the bottom so im thinking i will shove a piece of foam behind the slats that should slow the intake
SOme people rubberband the foam infront of the slots