Gypsum Calc. Chloride Epsom Salt CaSO4 CaCl2 MgSO4 2.4 6.8 5 1.7 4.7 3.5 sparge to 10 gallons
Based on boiling 15.50 gallonsliters at 1.088 for 120 minutes, this will decrease your wort by 2.00 gallonsliters, bringing your after boil OG to 1.099. You wanted an OG of 1.103. It looks like it will be under.