That does look pretty spectacular!
I always wonder how people handle having pests in their system, not just display, longer term, when they take care of it with a local solution. I guess you'll just have to keep them at bay in both tanks. It would be neat to see if you can get berghia to survive, and maybe even spawn/thrive in the frag tank without predators.
For an ATO, I went with a 15g acrylic container from online, and I've been extremely happy. My troubles are more from user error while messing with the pump and programming, than with the container or even the stock ATO setup. I'm using the neptune ATK/pmup/FMM. So far so good, knock on wood.