Agree with, jgira. However, nudi's are fairly expensive and don't mix well with some tanks--like wrasse dominated tanks. The 2 methods that worked well for me: peppermint shrimp, and using a small industrial syringe filled with lemon juice. I found the aptasia needed to be fairly large to use the lemon juice method, but when you had a direct hit, they shriveled up and died.
There is a lot of info on this and you will find a differing array of opinions on what works best, but from everything I've learned through reading and trial and error, you'll typically find these methods like Red Sea and others don't work. GL