The normal salts added to "Burtonize" your water is either just gypsum or Burton salts (gypsum and something else). They help you in extracting bitterness from the hops, so they are necessary in the boil. Adding them know, as I understand it, would be useless.
MOD EDIT: Sig only takes up 6 lines now. Fermenting: Apple cider x 2, Doppelbock, Red, Oatmeal Stout, West Coast IPA x 2
Bottle conditioning: RIS
Keg conditioning: La Fin du Monde clone
On tap: Maudite clone, Double Munchen, Oktoberfeast, Oktoberfest Pilsner
Planning: Brewed in 2011: 22 (2010: 15, 2009: 29, 2008: 21, 2007: 1)
Wine made in 2010: 6 kits (2009: 19, 2008: 30)