. I am assuming they are pretty close but I have no idea . I was thinking in that section as well. Reef Zen makes a mushroom box but I was thinking I might be able to turn into an intank fuge, they also make a copepod hotel that I think might slide into one of those sections But I’m not 100% sure on that.If the lagoon's sump section is similar to the nuvo 20's, I'd put it right in either one of the first drain chambers. The upside down T section where the return pump sits gets very little flow, not to mention it's hard to reach in to those areas.