i would skip the hermit and just add snails if you like. there is a good chance the hermit will kill the snails. plus, i haven't seen the benefit of having hermits in the tank, other than watching them climb on the rocks. if you are set on crabs, i like the emerald crabs better. at least they don't kill the snails.
as for the picture above, what are you referring to, the pump itself? i went to the aqua euro website and it seems like either that pump is from their european line, or it's been discontinued. can you take a shot of the skimmer itself?