4 Gal Mash Water - 103 Ca, 9 Mg, 23 Na, 85 Cl, 104 SO4, 10ml 10% Phosphoric
Based on boiling 6.50 gallonsliters at 1.043 for 40 minutes, this will decrease your wort by 0.67 gallonsliters, bringing your after boil OG to 1.047. You wanted an OG of 1.048. It looks like it will be under.