Rimless or rim, internal or external overflow

[Bent]

when one says external overflow, this is what comes to my mind. :reading:

 

[shane reef]

They are clean looking on the inside, is it worth the sacrifice of having the box on the back?

 

[MD Aquatic]

there isn't a splashing issue with rimless. I have one. If your returns and powerbeads aren't agitating the surface too much you won't have any issues

 

[Bent]

They are clean looking on the inside, is it worth the sacrifice of having the box on the back?

Id say no more than having the space taken up within the tank itself.