This is my personal experience with Lye. I read the article followed it to a T. Mixed correclty, turned off powerheads, etc.
Once using it, the aiptasia quickly became burned and appeared to disappear. It creates a cloud or fog that hugs the rocks. Within a couple of minutes of using the solution, my yellow tang and hippo tang bombarded the rock and began eating the solution. Obviously I tried to get the tangs away from it. Even used my turkey baster to remove a lot of it before turning the power head on.
After a couple of minutes. Both of the tangs had white mouths, apparently chemical burn. That day, both fish acted normal and ate pellets along with sheets of seaweed. Within 2 days my hippo tang was dead. 2 days later my yellow tang was dead.
None of the other 8-9 fish came near the solution or ingested it. None of them were harmed and are still extremely healthy. Luckily my Purple tang stayed away. If it died, I would of gone postal.
Also, the aiptasia did not completely die off. It did come back. I removed the heavier infested rocks and bleached them. I will add them back once they are recured.
Again this is my personal experience. I took the risk, I learned my lesson. I will not try or recommend someone to try it. I will recommend Peppermint shrimp. I have noticed a decline in smaller aiptasia. But the larger aiptasia, I tried Aiptasia X on it, with decent success.
Good luck.