Here is my .02 cents on what has and hasn't been said already.
Don't scrape the rock, like yetee said, you will be spreading them all over. I didn't know crop dusting them would work, to me that would make a mess and wouldn't kill off the big ones. I would get some type of Joes Juice or AiptasiaX etc and inject which ever ones I saw. Then when the tank is cycled I would get a bunch of peppermint shrimp depending on your tank size. The peppermint shrimp may be hit or miss, so thats why you get a bunch of them.....this way your odds increase on getting some that do eat it. However, they do typically only eat the small aiptasia, so inject the big ones. I have either 5 or 6 peppermint shrimp in my 180-gallon.
The only time I was truly Aiptasia Free was when I had a Copperband. However, even though he was eating Mysis and bloodworms he still died after about 5-months. For this reason I would not recommend a Copperband. But for getting rid of every single Aiptasia, he was awesome. I never did see him eat one but all the aiptasia disappeared after adding him.
If you are not going to have coral then there are other much hardier and more of a sure thing to eat aiptasia butterflys out there. For instance a Racoon Butterfly. If you are going to be FOWLR
then dont even sweat it until the cycle is over then add a Raccoon Butterfly and he will eat them all and keep the tank aiptasia free and you won't need peppermint shrimp either.
BUT, having coral is lots of fun, so be certain you don't want a reef tank before adding a Racoon because I hear they are very hard to catch.
EDIT- I just realized this is in the "REEF" Forum and not the "FOWLR
" Forum. Forget what I said about adding a racoon... I'm going to bed now. Good night.