Spot on! Mini fuge. I have a tiny ball of cheato in there (can't really see it in the photo though). I'm hoping it will grow behind the screen, sucking up nutrients, and providing a breeding ground for pods. I tried just adding cheato and jamming it in a corner, but it blew around the tank irritating the corals.
I'm thinking about making a long shallow screen to put cheato in along the back of my main tank. It'd then be exposed to the flow from the gyre, and light from the Razors, which should mean it'll grow nicely. Being trapped high up, and right against the back wall will mean it shouldn't cast a shadow over any corals. Any that pokes out will be food for the algae eaters, and it'll be a nice breeding ground for pods in the main tank.
Thought I'd try it out in this little tank first.