Please Help With Filter System For 2 Nano Cubes...

[xxBarneyxx]

I'm planning on building a corner unit which will hold two 30cm cubes. These will be planted nanos with 1 Betta in each (and possibly a few corys and shrimp).

There will be one tank above the other so I was thinking of using one of the external filters I have to take the water from the bottom tank and feed it back into the top take then use some kind of over flow system to trickle water from the top tank to the bottom one. All sounds great but I have no idea how to do this Also I dont want to much surface movement on either of the tanks.

Can anyone point me of the direction of informaiton on how to set this up?

In brief I want to:
Use one canister filter on two tanks (one above the other) with little or now surface movement and not lots of hardware inside the tanks (or visable).

(edit: title should have said 2 not 3).

 

[Rooster]

I would summon all my bravery, and drill the top tank... so you can fit an overflow (wier ?) I'm planning on something similar, you 'can' use a syphon, but my worry is that IF the syphon pack in, then all the water gets pumped into the top tank, and onto the floor !
I presume a local fish shop, or glass merchant would do the deed too....
Probably go with a bottom drill, I doubt your little tank has a tempered base ?