I had a large colony that had a zoa pox and it got pretty bad. I tried a number of dips except except I never did try Furan 2 because I wanted to see if my next method worked. I found a thread with a guy mentioning he put alittle more flow on the colony with a powerhead and would physically go through the colony and pop the little "zit" looking things containing the white goop. I was concerned that the pox would spread to my other zoas but I found multiple people that tried this method and never saw it spread. I have about 30 different types of zoas so this was a major concern for me. I decided to take a risk and it worked wonderfully. I pointed a little nano koralia toward the colony just far enough away from the polyps so they wouldn't stay closed out of irritation and poked these little zits with a tiny flathead screwdriver once a day at new spots over the course of a week or less. You'd be surprised how quickly the polys healed from literally having holes in the stalks of the polyp from where i popped the zits. This colony is pretty massive, probably about the size of two softballs side by side. Anyway, its been about 3 months since my "treatment" and I haven't seen the pox crop up since. I hear great things about furan 2 but the above method worked wonders for me so I never gave it a shot.