Different reefers have different successful method of dealing with Aiptasia. Some find using Aiptasia-X or Joe's Juice to work for them, while for others (me included) it did not work, and in fact made it worse.
Some used Peppermint Shrimps to eat the aiptasia, though there are also reports that their shrimps won't even touch the aiptasia.
For me, when aiptasia-x didn't work for me, so I tried the shrimps which cleared some of it. The remaining which for some reason the shrimp won't clear, I simply took the rock out and chip the infested sections away, haha.