I will ALWAYS recomend peppermint shrimp for Aiptasia. I have tried the lemon juice and it has never worked for me. Targeting them with kalk has worked for me, but the best thing that has worked is ....... Get a needle fill it with Lugols Solution, and inject them with that. If you get them right in the base it just takes a little bit and they are Done Son. This has worked for me 100 % of the time. Be careful not to use to much because you dont want to overdose your tank with iodine lol. Normaly if there are a few in there I'll wait to get them and not dose the tank at all for about 2 weeks, then I try to kill them all at once.
90 gal bowfront mixed reef, 2 250 w mh,2 48" t5 ho for actenic sup.