I've been in contact with Kent on number of occasions as well as spoken to reps at the LFS. Kent salt is IO salt with Kents additives put in. Kent salt is produced and packaged by IO. Kents reasoning was that IO has the cleanest, most up to date, most controlled enviroment in their labs. Kent made the judgement that it would be more cost effective to have IO just put in a TOP SECRET
set of ingredients. As I said before, if I had a fish only tank I would use IO, but I know a number of people who use IO in their reefs and they do pretty darn well with it.
I guess I got defensive as I've had nothing but trouble with the BioSea Marine Environment stuff. I hate to see anyone use it.