I kalked a few aptasias that appeared on some new corals I got and had a blast! They dont eveen know whats coming as the needle gets closer, closer then you see their guts fill with white paste. Of the ones I kalked I dont see any signs that they will come back. The kalk left a little blob like toothpaste where the aptaisa was but no signs of the buggers! Right now this is my only option for them until I remove the dragon wrasse from my reef, then I will stock a few pep shrimps to prevent reoccurence.