Bloomington water is great stuff. Its pretty much just runoff from the hills with a little mineralization. Its no wonder that Upland Brewing can do such good things with the water.
Definitely, don't add alkalinity unless its needed to keep mash pH from dropping too much. I also caution against using baking soda for adding alkalinity unless you really desire the sodium content. It can cause saltiness and harshness if it is raised too high. Pickling Lime may be a better way to add alkalinity without sodium.
The sulfate level could be increased markedly, if that is your taste preference. I like 300 ppm sulfate for pales. Its not sulfury to me at that level.