A balanced 8" with about 1000 lph of air will work for you. If I remember correctly the g3 is a 6"with the sedra 5000 and i'm sure it worked well on your 120. My favorite 8"skimmers are atb840v2, aquamaxx cone 3, em300, sea side aquatics cs2 or es2. All of these use sicce pumps and every one of these will be a good choice.
Thanks Drae! Ill check those out!