Thanks buddy!! I was looking for this exact info.
Looks like Baltimore's water is pretty low alkalinity, which is good for lighter or light amber beers.
I did some calculations using John Palmer's Excel Spreadsheet found at the bottom of this page
To make a very pale ale, SRM 1-6, add about 2-4 grams (1/2-1 teaspoon) gypsum per gallon of mash water, which will raise the calcium content of the water by 60-120 ppm; or you can add 4-6 grams (1-1.5 teaspoons) of Calcium Chloride for the same effect (raises calcium by 80-120 ppm).
To make a darker beer, you'll need to raise the alkalinity. Add either Chalk (1.5-3 grams, or 3/4-1.5 teaspoons) or Baking Soda (8-12 grams or 1-1.5 teaspoons) to raise the residual alkalinity by about 180-200 ppm of bicarbonate.