Drilled aquariums?

I believe it's for SW - the corner of the tank is walled off, has notches for overflow, and there is a pipe that connects to the drilled hole (which is quite large) that carries water from the tank to a wet/dry type LARGE filter.
I could be wrong though, this is just what I seem to remember seeing at the LFS.
I think that the system can be adapted and used for FW, it's just more the norm for SW.