Design for nano gyre tank

[Hangfire]

I'm wondering if it would not still be possible in a tank like this to have overflow(s) and a sump beneath, some place to put a skimmer, heater, whatever? What do you think?

I'm also curious if you given any thought to the possible problems with having swimming critters in such a tank. Is there something to block them from moving into the area underneath - I'm really thinking of animals that might have trouble getting out, like hermit crabs and the such. This type of tank sounds very interesting.