I recently purchased a sump. It has a small area for bio balls and seems to be mostly a refugium. I was wondering if someone could tell me how it works. I know how a wet/dry works and I understand that part. Past the bio balls is a square area. It only has one small hole opening into the side area. There is no opening from the bio chamber into this part. The side has baffles. One has a small hole the other seems designed for water to flow over it. At the front of the side chamber on the bottom is a baffle that is open at the bottom into the part where the return pump goes. Not sure how to make this run past the wet/dry part.