Depending on the style of overflow and the possibility of a clog or failure, There would need to be at least the last set of baffling to hold water in the center chamber where the heater is being utilized, as well as a bubble trap at the return area and to limit the amount of water the pump would be able to return to the display.Easiest would be no baffles and bags/containers of media. Baffles are needless in my opinion![]()
If you didn’t the pump could pump all the water out of the sump.