Recommended Skimmer for 50G

[Buccaneer]

Hey everyone ... this may sound odd but I have only had one skimmer and it is a dual beckett so have no clue as to the " store bought " brands and what is good.

The tank is ( 50G ) in the wall of a store and there is not alot of space so I was thinking of a hang on back variety ( there is no chance to drill for a sump either )

Of the available models is there a recommended model that wont put microbubbles back into the tank and is pretty maintenance free ( he has to train some staff members to look after this tank )

Thanks for the input