Speaking from experience i wouldnt put a nem in that aquarium... not so much the growth but the movement, mine moved every few weeks until i got MH lighting over it. And when it does move you have to relocate your other corals or else they get stung. Add to that the fact it will likely take up residence where you cant see it 90% of the time. I would definately recommend somethign else for your clowns to host. One of my clowns prefers a candy cane coral to host over the nem. They arent picky, below is a link to probably the best alternative to an anemone though...
http://www.garf.org/39/fish/pict.html
Cheers,
Ken