Tell me this isn't Aiptasia!!

[Myanth]

I have had great success with straight calcium. Just take the tanks regular dose and mix it with as little water as possible to make a liquid. Use a syringe to get it right in the little buggers. It melts them pretty quick, just make sure you have nothing directly beneath or down stream as the calcium with hurt them too. (still have a scar on my orange cap)

Also a copperband butterfly will quite often develop a taste for them and will get rid of the smaller ones pretty quickly although they tend to wreak havok on any ornamental feather dusters that may cross their path as well.

Hope that helps.
Mike