Flower,
Finally I get to help you instead of the other way around
I don't know about the lemon juice. I only tried it on one aiptasia and all it did was suck in and came back out later so I chalked it up to not working. had 3 peppermints and they went MIA after a couple days, never saw them actually eat one. Allthough they went crazy for a piece that was dropped into thier tank at the LFS.
SOOOOooo onto what worked for me.
I bought 100 lbs of live rock for 75 bucks about a month ago. the only downside was that it was FILLED with aiptasia probably about 200 or more. some huge, some just teny tiny.
Finally after trying all the cheap methods with no results I found a site that bosted kalk mix as the answer and not only that but they said you can make it out of mrs wages pickling lime which is about 4 bucks for a 20 lifetime supply of the powder. Just mix it up to a paste thats fine enough to get syringed through you applicator but you don't want it watery so that it doesnt stick to the rocks either.
it works just like aiptasia x just get them to touch the tip and they think its food and then just paste it on thier little faces. they will sometimes be quick enough to retreat back into thier holes so just cover the hole with the paste. Leave it on there for about 45 minutes and then suck the little bugger out with a turkey baster.
there are a bunch of reasons why I beleive this is the best option...
1.) you cover thier oral disc so they can't blow out thier little spawn seed all over the tank and make babies.
2.) you actually remove them from the tank
3.) kalk mix is widley used (in moderation) for helping with calcium and PH levels in tanks anyways.
4.) you usually get most of the mix you pasted on the bad guy back up i the turkey baster with the baddie so its not flying all over your tank.
5.) its super cheap and easy to make
make sure and turn your power heads off first so they don't blow the paste all over on your other corals.
I treated my LR in a 55 gallon tank that was seperate from my actual 90 gallon becuase I didnt want to introduce the aiptasia into my system. but the LR i got had a kenya tree, a nice chunk of green star polyps, ricordia, a rose bubble tip anemone and a few brown mushrooms in there while I was treating. the only thing that didnt survive were the aiptasia
also had a bunch of snails and crabs that came witht he rock that stayed in the tank and I found my peppermint shrimp still alive on the bottom of the tank when I fianlly moved the rocks out to put in my display tank.
Good luck, hope this helps