Yea, I think the key are nutrients (proteins, lipids, etc) as mentioned. If you don't want to get rid of you skimmer, you might try Kent's Coral Accel. I stopped using it for some period of time, thinking it wasn't needed, and my xenia hands have gotten skimmpier. When I was using it, they were lushious (sp?) and full. I haven't have them long enough to split yet, but they are in the process of doing it now.
kris