Christy,
Can't find the RC thread that discusses Seachem salt's really high level of boron. Randy was adament that such high levels in a reef are not so good. Did, however, find an article on
Boron in a Reef Tank. While the article is all about boron and what it does chemically in the home reef, Randy does discuss Seachem salt. Long read, but might explain a few things about what might be going on with your new frags...
http://www.advancedaquarist.com/issues/dec2002/chem.htm
BTW, there are two Seachem salts on the market now, one of which has just started being shipped. Here's Seachem's site for more information on their two salts...
http://www.seachem.com/home/home.html