Um I believe I had a TON die in my tank.....unfortunate. I caught them in my overflow filter sock once the aiptasia were gone.....they float to find a new location. It worked so GREAT for me...I just wish I had some more I could send you. If you can get them breeding they work like a charm. You will be able to see the spiral shaped egg sacks under rocks....very easy to spot. Check out
www.saltyunderground.com to check for compatibility with your fish and inverts. I made a $150 and some corals for the ones I sold. I work at a LFS and bought the 3 cheap, so it worked out great for me. Salty underground has great prices even compared to wholesale. It does take a LONG time for the aiptasia to disappear but I tried the same things you've tried. The nice thing is they eat the WHOLE aiptasia not just the top and then the aiptasia grow back.......when they're gone they're gone. Man I had a hard time getting rid of these dumb things.....I am thinking of setting up a breeding tank for Berghia...SUPER easy to breed in a small tank...just place them all together...simple.