Nothing in reefing is an exact science is probably the second biggest thing I've learned after the solution to pollution. I was targeting adding the 3 at once, but my concern is the impact on the bioload of adding these 3 big suckers all at once to my almost 3 month old 155 gal tank which is currently FOWLR. I'm going to wait a couple more months probably until I move over the corals.Tough to say, tang compatibility is just not set in stone, too much individualism in each case. The argument can be made to add the most docile first and then the more territorial. The counter argument is to add them all at once so that no fish has an established territory….