So I have been looking to add a refugium to my sump but with the lack of available space I didn’t think it would be possible. Then I found the AR-Pro Refugium A Add On Refugium / Mud Filter 15″ x 5″ x 18 1/4″. It fits perfectly between my sump and UV. I wrapped the back and side with foil and added a Chaetomax 18W Lamp on the side and I added some miracle mud, 2” cubes , a small Aquatop circulation pump, a jar of pods, and some red ogo. It all fit like a glove once it was plumbed in.