I am not so concerned about teh filtration, although I am not a fan of magnums. I woudl eb more concerned about aggression. It would work for awhile if the fish are young, bt i fear as the fish grow there will be problems, but then again you may get lucky with some mellow fish, but IME salvini's acn be failry nasty as well as gt's.
PS. You can get a true GT from rapps, although I think the common saums are prettier