I have a coperband butterfly, haven't seen one since. That's the only method i used. Two-3 weeks after i put him in, all gone. Couldn't do shrimp or nudibranch with my wrasse. Didn't want a file fish cause they'r ugly. Copperband eats frozen clam, mysis, and just about anything except pellets, and has left all corals alone so far. Been about a year, he's 4-5 inches. He was eating at the store so i bought it. The aptasia was multiplying quickly, now it's been gone from anywhere i can see.
The kalk method alone will never do it.
12-24 peppermint shrimp at 8 bucks a pop won't be cheap, and they'll likely wipe out your snail population too.