you have a way to beat them but usually not with permission from the masses to do so, they only allow the common approaches.
I have a link where a rip cleaner took apart his tank, cleared out 100 overgrown mushroom frags who attach just like aiptasia, using a special surgical removal option, put it all back shroom free in one pass. aips work the same way, and they dont fragment like the masses claim they're just easy to beat with surgery but most wont do it.
they fragment from gluing, boiling, but not our method ours removes the mass in one pass.
your tank being too large is the likely issue/too much work/but they're beatable all right, in one pass. Ive done it, and had hundreds of my nano reef friends easily beat aip on round one. getting large tankers to do the job takes real sales skill, they usually will not do it they'll keep the anems.
if you want to run one test rock, watch how well they stay gone compared to other methods you'd try as comparison. we have special means
aiptasia are easy to beat if you approach it the right way, and when there's 5 vs 55