I got some from elite reef 3 months ago, I think they get it from a guy from pueblo.
I got them for aptesia and they didn't do anything. That was waste of money in my opinion.
Neptunes usually has them. I had a huge problem in my 150. Got like 10 burghia, 15 peppermint shrimp and a copperbanded butterfly. Aptasia is gone. Not sure who did the best but none visible now.