I agree with jrwagner, I use peppermint shrimp for my reef tanks - they keep the worms at bay, and I also have added a CB Butterfly in the past (lucky for me, he didn't care for the shrimp, and left him alone). I typically stray away from using chemicals if not absolutly necessary. If you have the patients, and a quick hand, you can remove some of the larger aptasia with tweezers. LOL you won't get them all, and it may just piss you off (they are fast little f**kers!! LOL), but if you get bored, lol, try it. I remove the larger ones that way, but for smaller ones, or ones really wedged into a crevice - CBB all the way. Vinegar works too, but be carefull if you use that, it's acidic, and can screw with your water, and harm the other inhabitants. If you go that route, make sure you are patient, and not frustrated to the point where you just want to squirt the hell out of them, lol. As far as other chemicals - like I said, i typically steer clear unless I really need them, but the link DEL posted has a product on there that i have used in the past with good results.