Lovin' your build
I'm still following along, regardless of what has happened in other threads
I think peeps got out of control and hope you didn't take it too personally
Thoughts/feelings are hard to decifer in a forum when all you see are words
So, what steps are you taking while you're adding all these new fish to your 'new' system ?
I hope you're using some kind of bacterial boost stuff to help you over ammonia humps/get you through cycles
I'm thinking something such as Seachem Stability, although there are others out there that I haven't used
From what I can decifer, it looks like you're not quarantining your critters, or are you ?
As for your tang not eating the Nori, have you tried a clip on the glass, such as a Veggie Mag ?
If 'any' of your other fish will eat from it, I'd almost guarantee your tang will be right in there like a fat kid on a smartie
Another thing to try is to soak some Nori in a dish with some tank water, then drop in small pieces and see if the tang goes after them, or sees other fish do so
Good luck dude !