Just a ?
 

Is it possible to do a 14g tank with an external overflow? Or is the tank going to be to small? I was thinking of a 20g sump so I could fit a skimmer in it, and a small pump.

I was thinking of adding a sump too but I dont know where I would even put it =/
Maybe if I got a different stand ?

asherah

In theory no reason why an external over wouldn't work, limiting factor would be how much flow you planning?

Any reason an external need?

Just so I could keep a little more room in the tank, it is for my sea horses, I just want an overflow system, why do you think there would be to much flow?

My comment about flow being a consideration goes towards the length of the weir you're needing plus the size box to be built to handle the bulkhead you'll use. My point being on a small tank there's smaller panels of glass to cut into.

This RC calculator give length of linear weir for flow (though it doesn't give height of water about) plus bulkhead.

The overflow calculator download (Excel spreadsheet) in this link can give an idea of size needed if using a slotted weir.

Maybe something to consider was Fish's approach on his pico visible in the first video maybe not a overflow in a true sense but wasn't obtrusive.