Based on boiling 7.20 gallonsliters at 1.047 for 60 minutes, this will decrease your wort by 1.00 gallonsliters, bringing your after boil OG to 1.054. You wanted an OG of 1.055. It looks like it will be under.
V V Astringent Mineral content, I am sure it was from the Gypsum. big mistake, ruined the whole batch, barely drinkable V V