I'm with Tumbleweed. I've given up so I bought the big expensive bottle of aiptasia-X and I nuke them every once in a while. They'll grow back, and then I'll nuke them again. I'm hoping that eventually they won't have the energy left to grow back. That might be a pipe dream, but nothing else works short of starting over again. I had peps that worked quite well and then died, then the aiptasia came back. I ignore the ones I can't reach, even though I know they are aiptasia factories. I've spent HUNDREDS on berghias that just died without taking down a single anemone, I'll never try them again, they are way too delicate.
I think the key is to come up with a less annoying way to kill aiptasia on a regular basis. I use the syringe but it is hardly convenient to stick your arm in the tank with the syringe. My idea is to use something similar to the "syringe and tubing" spot feeding tool that many people us. Just hook a syringe to airline tubing, then attach the tip of the tubing to an acrylic rod and see if I can get one of the syringe tips to fit on the end of the tubing. That way I could kill them without getting my arms we and also while looking through the front of the tank.
They are bastards and we should kill them on site.
V