Gypsum Calc Chloride Epsom CaSO4 CaCl2 MgSO4 0.1 0.8 1.2 0.1 1.0 1.5 before sparge 13.5 gallons, stop @ 3.5
Based on boiling 13.90 gallonsliters at 1.044 for 60 minutes, this will decrease your wort by 1.00 gallonsliters, bringing your after boil OG to 1.047. You wanted an OG of 1.048. It looks like it will be under.