I'm curious about something that hasn't been mentioned yet. You said you just recently got the nem, what color is it?
Given the right environment (lighting, space, and some feedings) you have a decent shot at keeping a healthy sebae. Unfortunately, in my experience, it has been VERY difficult to find a healthy one at my LFSs, in fact, I don't know if I've ever seen one (doesn't mean there haven't been any, I just haven't seen them).
If you begin with a bleached one, your chances of sucessfully keeping it are decreased quite a bit.
If it is a beautiful white, with stand out purple tips, it's bleached. If it's a tan, beige, brown (most common colors), and now the purple tips aren't so striking because of the color change it's healthier.
We had PC lighting when we got ours (it was bleached), and it wasn't responding, even with regular feedings, it wasn't attaching, and looked really bad. I'm still amazed it didn't die, I really thought it was a goner a few times. We noticed a turn around once we upgraded the lighting. We went to MH, but that was something we had planned on doing anyway. Others have been successful with other types of lighting too, but I felt this was easiest, and would accomodate future corals we were hoping for.
Ours is now healthy and happy and we don't feed nearly as often as we did in the begining when it wasn't. We do once every couple weeks or so. However, this would not be a good feeding schedule for a bleached one.
Good luck!