I've been pondering what kind of salt to use and came across these interesting links.
I thought I'd share them in case anybody else wants to read up on salt ;)

Just the basics (alk, calcium, etc.) for the most common salt mixes:
http://reefcentral.com/forums/showthread.php?t=1714505

This one is the one that got me interested in Tropic Marin Salt:
http://www.advancedaquarist.com/2005...hterm=salt mix
Not that I necessarily want to breed urchins but I figure if it's good enough for urchins it's good enough for me.

Inland Reef Aquaria Salt Study (shows heavy metals, etc.):
http://www.advancedaquarist.com/2005/11/aafeature1

Feel free to add!