Jeff will be able to speak more directly about this, but I can tell you what I understand.
Quite often we will get an incredible coral in, it will have awesome colors, then once it hits the system it would lose a lot of it's colors and brown up. Who wants to buy brown coral? We made several changes to our system, we believe the most significant was the use of SeaChem Reef Salt. We now are able to retain the colors that we see when we take corals out of the bag, this is huge for us. We have never had issues with coral growth in our facility, the stuff grows like crazy under natural sunlight, and we have good extension of the polyps and such too.
I suspect we could get some of the same results (possibly better?) with some of the other brands of salt out there, but right now we are liking what we are getting out of this product.