Aptasia is like herpes, once you got it its never going away. You can treat it periodically but there is no cure.
Peppermints keep them at bay, but only eat smaller ones so you will still have to take care of the larger ones manually. I prefer a kalk paste made of 50/50 kalk powder and water. Its the same as every aptasia killer on the market but cheaper and stronger. Turn all pumps off then use a syringe to dump it right on the mouth, then wait till they retract and cover them with it. If you can a cap of epoxy is a good idea. I usually wait about 3-4 hours then turn the pumps back on. Just dont get it on corals.
I also got myself a 3 watt laser to burn the ones I couldnt reach. It works but not great and its time consuming at about 1-4 minutes per aptasia.