Jeff, I wouldn’t go as high as 100 ppm for BOTH chloride and sulfate. In an IPA, 100 ppm sulfate is a good starting point. But adding 100 ppm chloride with that is inviting an antagonistic flavor impact. I like to keep chloride in the 50 ppm range when I’m boosting sulfate above 100 ppm.
Another unfortunate thing that an extract brewer needs to watch out for is the very high sodium content of Briess extracts. At a reconstituted gravity of 1.045, a Briess extract wort contains 100 ppm sodium. Add that concentration to any sodium that the brewing water already contains. Double the wort gravity and the sodium content of the wort goes to 200 ppm. This problem with Briess extract comes from them using the local Chilton, WI tap water which is ion-exchanged softened by the City prior to distribution. I’ve already had a long conversation with the water system manager in Chilton and he confirmed the water quality they produce for their customers. Because of the high sodium content, I have to recommend that extract brewers consider using other extracts for their brewing.
By the way, this sodium result for Briess extract applies to all of their liquid and dry malt extract products. All the other ions in their extracts are in appropriate ranges.