If you kill it with a kalk paste (my preferred method), joes juice, or aiptasia x, I recommend turning your pumps off while you apply the paste and leaving them off for 10 minutes. When threatened aiptasia tend to release a larvae into the water which can cause them to quickly repopulate. That's why I like kalk paste. It can fully cover the aip, set, and kind of cement them in. Keeping the pumps off helps to prevent them from spreading around the tank.