Take the rock out of your tank and let it sit in the sun for about a month. This method is guaranteed!

Seriously...
Nudibranch, peppermint shrimp, copperband butterfly all work.

Copperband has worked wonders for me in the past but I have had little luck keeping the fish alive for more than about 6 weeks.

Raising your calcium level can help control aptasia. Changes in water quality always upset anemones.