I personally do not like the filter sponge in a reef tank for nutrient related issues. I made this piece up that slips into the area a filter sponge would go that also adds surface disruption for aeration to the water and then directional baffling to slow the flow and prevent micro bubbles from entering the pump chamber. I designed this for the RedSea Reefer 425 G2+ system but there are many common sumps this will fit if you have a Reefer Sump. Remember to use reef safe filament. I printed this with 75% infill so it will not float up during feeding times. Make sure to adjust your infill percentage or it will float up and raise your sump level once the return pump resumes. Support is also on build plate only for the overhang.

Bambu Lab

No

Yes

75