12 weeks does not equal 1 year. If you are disappointed that 12 weeks is the safest amount of time to completely rid your tank of ich, then, just take the 99.7% and put them in at 8 weeks. Is an extra 4 weeks of a fallow tank to be assured there is no ich not worth it? That's for you, and everyone else to decide.
Honestly, I'm currently in a fallow period right now, and I'll be adding my fish after 8 weeks. There are way too many opportunities for ich to be brought into the system for me personally to care (I don't QT corals or inverts for months, I just dip em') .. but yes .. ich has been known to survive for 12 weeks.
It makes perfect sense. Why do people QT fish when they first get them for ~4-6+ weeks? It's to check for signs of ich.
So week 7 he adds a cleaner wrasse that may have ich, and in 1 week, he's putting all the fish back into the DT. Well, that Cleaner Wrasse may not show symptoms for that first week, but he may have ich .. and therefore, all the fish would then once again be susceptible to getting ich.
He adds a fish to QT, he should QT that fish for at least 4 weeks, preferably longer, to monitor for ich. That means any fish in that QT has to remain in there for that time frame, aka, resetting the clock.
Not rock science, Mad Scientist :lol: