Kalk paste works well, though it will kill any coralline algae it touches too if it's strong enough. I had an aiptasia problem a bit back and I tried the kalk, which worked on individual anemones, but there were plenty of "babies" that were too small to see and treat which started popping up. The I tired the peppermint shrimp and the anemones were gone in 2 days.
I know pep. shrimp work for some people and not others--maybe it has to do with getting just the right species? Also--once your aips are gone, these guys might go after small anemones of other species if they're hungry.
Might be worth a try--they're entertaining little guys too.
Christine