I'm new to reefing and using a sump for filtration I was advised by the previous owner of the sump that the way its set up is the best way to use it but I feel I'm not getting the most out of it the way it is as I'd like to add my nyos quantum 120 skimmer to it there is a large empty compartment in it not getting used any advise pls the tank is a 120ltr cube and 30ltre sump