What to Add to my New 10 Gallon Refugium?

I setup a 10 gallon fish tank as a Refugium, and I have no idea what I want to do with it. Here are a couple of my ideas.

Put fish I can't have in my 55 gallon reef tank. (dwarf lion fish or pipe/sea horses)

Make it a Nitrate filter with lots of plants.

Make it a place to raise coral in racks and sell.

Maybe a combo like pipe fish/sea horses and to raise coral?

What are your ideas?
The first idea-live rock rubble,sand and macro-algae.

It's to small for a dwarf lionfish and I'm not sure about seahorses/pipefish.They will need a slower flow,though.
You dont want to put livestock in it unless you have to. I have a CC star in mine because he`s banished from my reef tank since he`s not reef safe. I would put sand and macro in it.