Reefs Edge has a used mag 18 when I went over there the other day. They also have a few used mag 12's but Mark is using them to cure a bunch of LR so I am first on the waiting list once hes done with em. He also has ALOT of other used equipment including tanks, lights, skimmers, calcium reactors, heaters... I can go on forever. I just picked up a used 300w titanium heater for $10. Can't beat that
I hope that helps
-Matt