We ended up getting a Copperband Butterfly - which worked wonderfully on the small and medium aptaisia (we tried peppermint shrimp first, but they didn't seem interrested in the aiptasia). We had two aiptasia that had simply gotten too large for the butterfly to deal with and those I had to inject with a mixture of marine buffer and hot water. Worked like a charm - and it didn't add any foriegn substances or chemical to my tank. I mixed about a teaspoon of buffer in about a quarter cup of very hot water - and drew that into the syringe. The hot water alone (for me at least) did not work and the aiptasia recoved in a day or so.
The butterfly is doing great, no return of aiptasia in the main tank... now if he would only fit in my refugium (where I evidentially picked up several aiptasia from my last order of algae from IPSF)!
Jennie