Kessil actually sits on the reflectors.. I used a 2.5 inch while saw bit and drilled through. If you have the aquaticlife fixture you will have to remove the reflectors and reposition the ballasts to the outside. To do that the led drivers will have to be moved toward the middle of the fixture then move the other long black box to where the led drivers where. That makes room in the center of the fixture for the kessil to sit