What do you keep in YOUR refugium??

My husband got my refugium "online" yesterday. It sits on top of my rubbermaid stock tank and is fed by one of the return lines from the main tank and then gravity flows back into to sump via a standpipe that draws water off the top.
What do you keep in your fuge? I have a small temporary one set up that I will transfer those inhabitants into the larger fuge tomorrow. I think I'm going to just stick with some small pieces of live rock, chaeto, bristle worms, limpets, small serpent stars, some yellow sponges and hopefully pods and my mandarin fish. I've had a mandarin in my 90 gallon for over a year and he started looking skinny about 8 weeks ago and I have been really worried about him. I guess I shouldn't have added a sixline to my tank because that must be what changed his pod population. Anyway, in the week that he's been in the temporary fuge with no competition, he looks less thin so I'm hoping that he'll do ok in his new home.
Any suggestions of what I can add to the fuge? What do you have in yours that I don't have in mine, and why? What would you NOT put in yours if you had it to do all over again?  

 

Have any experience with red algae?  I just wondered, it looks pretty.

 

hmm, I grew calerpa once in my old refugium but I took it out because I was afraid it would go asexual.  This fuge is big enough that I could keep it separated and grow a small amount.  I would love to have something natural to feed my tangs rather than nori sheets.  Luckily my hair algae seems to have disappeared but they never ate that anyway!
Are there any other kinds of algae's that are easy to grow and that tangs like to eat?