Wow - I had no idea people are still using torches to kill Aiptasia! When I was an aquarist at the Shedd Aquarium back in the 1980's, I remember the reef aquarist doing that, and I've always joked about it.....
The best control methods I know of (aside from not letting them get out of control in the first place) is calcium hydroxide slurry injections (with all safety precautions) or a good Australian copperband butterflyfish.
Jay
.5mm of 50/50 solution of Sodium Hydroxide and water works for me along with Pepermints
see if you can find a Berghia nudibranch awsome aiptaisia eaters and when they are done eaiting aiptaisia they die as aiptaisia are there only source of food.