these aiptasia were localized in one area, on a point of a rock. I boiled water in a pot and then held the rock in the water, just the part that had the aiptasia on it. Then after the rock cooled, i returned it to the tank. it does not cause a die off, as you have sterilized that part of the rock...nothing left to die and rot. it is dead and off.At least I have never had problems with it and i guarantee you, the aiptasia does not come back. just make sure the rock totally cools before returning it to the tank.