I took this pic at a local reefers house the other day, he has a multi thousand gallon setup divided between a bunch of tanks, he grows out Corals for money, but here’s where I got the idea from:
A 55 gallon drum connected to his sump that acted solely as a fuge. Obviously you can’t tell by the photo but those diagonal pipes are adding flow that keep the chaeto tumbling clockwise. Seeing a side shot of this, I get the sense would be sick.
For what it’s worth, while his sps do pretty good, he has a hard time keeping zoas their happiest given just how clean that fuge keeps his entire system.
Although, if I’m being completely honest, based on your “so that idea is dead” I get the sense you’re a very new reefer?
Sure, you might be able to pull off this fuge concept with a HOB overflow, but I’d argue that you’d be far better off with a drilled overflow, whether internal or external, and that’s not something I’d consider to be a casual experience for a beginner. It might make more sense to simply keep the hex tank on hand for when you’re ready for some new project in the future, but prioritize learning the basics within your biocube?
I’m only at about a year into the hobby and I’ve spent all 12 months of that in the same position that you’re in. Like “ok how about this idea for a tank theme? Scratch that. How about this one?”
It is obviously ridiculously fun but you’ll end up honing in on specifics instead of learning the most about the basics. I’d think you’d be better off with a theme less, normal reef in your biocube and figuring out what works and what doesn’t. I think the 2 AI primes should throw off more than enough par in an interesting spread that will allow you to accomplish one heck of a mixed reef, so pursue that instead of honing in on like, one eel, or only mandarins. I say this because my first thought was “garden eel garden” and I never followed that through. I also wanted a seagrass bed tank… never followed that either. IME you learn a lot more from following the standard progression and thus encountering the regular issues, than you do by focusing on something super uncommon or niche