I had a 20 long that shared a sump with my 60 cube. I made money on it so it was well worth the investment. I picked up a 45 long (half height 90) that I am going to make a frag tank out of. Can not decide if I want to tie it into my 120 or make it stand alone. I am leaning towards stand alone. Not only would it be a place to grow frags, but it would also be my back up incase something happened in my tank. Considering I had some sort of hiccup that cost me a few nice sized colonies this summer, I am leaning to the separate system. Also, I only trim from my display when necessary to settle turf wars, so I get lots of frags sporadically. If I had a separate frag system I could frag all the time.
