a sump for a nano is a cool idea, seems like overkill to me, but i'm sure it would be fun if you have the time/money/resources
Actually, it wouldn't be that expensive.
The sump itself: 5 gallon bucket and lid, rubbermaid storage container, or clear plastic file holder (all on the cheap side -- especially
Motor: aquarium water pump or fountain pump (less than $15)
Tubing System: airline tubing (cheap), check valve (also cheap), wider diameter tubing (probably a bit more expensive), silicone for sealing
Filtration: some PVC tube, creativity, and filter medium (cheap)
Heating: 25 watt regular heater (can be cheap)
Nano container: Nano aquarium, nice vase, pickle jar, whatever you can think of that sounds cool
You would also need to get (or borrow) an electric drill and find appropriate drill bit(s).
Some of those items you would have to get anyway for a regular nano, depending on how small it is. The other sump-specific things can't be much more than about 30 bucks total, if you are careful.
So, for not too much time and money, you can get all the visual effect of a nano without the water quality, heating, and filtration problems. Plus, I think the time and pain of super-demanding water changes on a tiny container would make this worth it alone.
If you like diy projects, this one is pretty simple and wouldn't be that hard or time intensive, aside from drilling the holes in the nano container of your choice, which is a bit nerve wracking.
as for the "fountain" idea, wouldn't water flow out of all sides of the nano unless it were tilted? you'd have to have it positioned right in the middle of the sump for it to overflow without making a mess on the floor, i'm just wondering how you'd suggest doing that? it's a neat idea, but i see it as very hazardous o_o
Yes! The cascading water would be the point.
Unlike the original diagram, the "fountain" setup would have 3 pieces, not 2.
Piece 1: the Tank (Almost certainly a vase, pitcher, or regular bowl of some sort. It would have to be see-through so that the betta — or whatever — could be viewed.)
Piece 2: the Overflow Base (Something decorative, and bigger than the tank, so it would catch the overflow. It wouldn't have to be glass or see-through. It could be a nice shallow ceramic bowl or whatever you like.)
Piece 3: The sump tank, safely out of sight.
The Overflow base would have water in it and would need a drainage hole at an appropriate place. With a base that doesn't have to be see-though for fish viewing or hold water almost to the top, like a tank does, that gives you more flexibility to place the drainage hole where you want it.
You're right — there's no escaping the drainage hole, unfortunately! Not with this way of doing a sump.
Here's an "artistic rendering" of what the fountain would look like:
OOOOOO <--- glass nano container (in the center of the overflow base)
OOO|000 < --- airline coming up through hole in nano container
------------------- <--- decorative overflow base
|| <--- the two tubes coming out of holes drilled in decorative base
||||||||||||||||||||||||||||| <---- Sump container, safely out of sight
You might need to finesse some kind of partial cover or lid (mesh?) for the viewing tank, depending on what you put into it, so nothing living escapes into the "catch" basin.