Gypsum Calc Chloride Epsom CaSO4 CaCl2 MgSO4 0.1 0.8 1.2 0.1 1.0 1.5 mash ph 5.02, adding 2.5 grams baking soda = 5.15 sparge start at 16 gallons, stop sparge at 10 gallons
Based on boiling 13.70 gallonsliters at 1.042 for 60 minutes, this will decrease your wort by 1.00 gallonsliters, bringing your after boil OG to 1.045. You wanted an OG of 1.048. It looks like it will be under.