Salts CaSO4 2.5g, CaCl 3.0g plus a quarter tab campden. WP at 77C, pitch 2.5mL of enzyme at yeast pitch.
Based on boiling 7.00 gallonsliters at 1.044 for 30 minutes, this will decrease your wort by 0.50 gallonsliters, bringing your after boil OG to 1.047. You wanted an OG of 1.048. It looks like it will be under.