My whole tank wiped out. How to start over?

Sorry for your loss

 

12 weeks?!?! it was my understanding that the life cycle of it was in the neighborhood of 6 weeks.

Marine Ich/Cryptocaryon irritans - A Discussion of this Parasite and the Treatment Options Available, Part I by Steven Pro - Reefkeeping.com

The lifecycle of the parasite is interesting and important to understand when evaluating a treatment. The stage where the parasite is attached to a fish is called a trophont. The trophont will spend three to seven days (depending on temperature) feeding on the fish. After that, the trophont leaves the fish and becomes what is called a protomont. This protomont travels to the substrate and begins to crawl around for usually two to eight hours, but it could go for as long as eighteen hours after it leaves it's fish host. Once the protomont attaches to a surface, it begins to encyst and is now called a tomont. Division inside the cyst into hundreds of daughter parasites, called tomites, begins shortly thereafter. This noninfectious stage can last anywhere from three to twenty-eight days. During this extended period, the parasite cyst is lying in wait for a host. After this period, the tomites hatch and begin swimming around, looking for a fish host. At this point, they are called theronts, and they must find a host within twenty-four hours or die. They prefer to seek out the skin and gill tissue, then transform into trophonts, and begin the process all over again (Colorni & Burgess, 1997).


Given that, I did Hypo for 6 weeks on my tank with several fish including 2 large tangs and was successful in ridding my tank of this parasite.

 

That article is 10 years old. Not that it makes it incorrect, but we've discovered things since then. There is indeed a much shorter average cycle time, but there have been some that last muuuuuch longer. Most people don't want to risk doing treatment a second time, so they wait past the point of the longest documented cycle.