Zoa's receding?

I am not 100% he was the sole culprit with the issue but what I saw sure didn't help them any.

 

I don't mean to hijack, but when you get zoa polyp what is the dip/quarantine method? I am just getting my tank together and ready for some corals so I am quite interested. Hopefully my emerald craps wont be such a bother!

 

I am reading that one uses a product called Lugols and mixes it with rodi water and does a 5 minute dip. I cant find the thread with the exact mix ratio but there are applications on the bottle. I am contemplating trading all my emralds for blue legs and snails. I hear they can get like 2-3 inches and that is not that appealing to me......