Salts CaSO4 2.5g, CaCl 3.0g plus 0.3g Kmeta and pinch of MgSO4.
Based on boiling 7.00 gallonsliters at 1.042 for 30 minutes, this will decrease your wort by 0.50 gallonsliters, bringing your after boil OG to 1.045. You wanted an OG of 1.050. It looks like it will be under.