The best method in my opinion is to smother the SOB. Works great with a lot of hitchikers. Smother them with epoxy. I recently layed down a mat of epoxy 5"x3" to smother some Xenia and GSP that got out of control. Works with mushrooms too! LOL. In some cases you may have to irritate them first so that they deflate. Or in the case of Xenia and mushrooms, scrape their heads off. Then, spread out a sheet of epoxy to the affected area. If any managed to peek through just repeat. After a few weeks I'll maybe take off the epoxy if it is unsightly. The area underneath is remarkably clean
Aiptasia in particular I have found quite easy to remove with this approach. A little ball of epoxy, smother over aiptasia, done.
Anyway, yes Doug, this is why I buy so much freaking epoxy
