The point i was making, is that 28 gal isnt "Nano", thats a fair size tank. My "2ft x 1.5ft x 1ft" is 16 gal. 28 Litres however, is Nano. But you wont get much more in 28ltrs than a few tiny fish, and some shrimp.
Is its 28 litres you want, you'll be better off with a Fluval Edge. But you could only have 23ltrs of pure shrimp madness, and a Betta, tops.
EDIT: Possibly ignore the Betta bit, it could be wrong. I think Betta's need to be able to gulp air every now and then, and im not sure they would consistently find the small air hole at the back of Edge tank.
Could be wrong tho.....