yeah i second the hypothesis of high temperature burning the leaves. It came on too quick and so severe I would not think it was a nutrient issue, ph off or not. Ya burned it... get your temperature down to around 80-85 at the most and get ur ph leveled at 6.5ish. Do NOT feed it water that has sat for more than 48 hours. I just take tap water and fill a reservoir with an aquarium air pump and airstones and let it bubble with the lid off for 18-24 hours, works perfectly. Those leaves are not gonna replenish themselves and ya the plant is in trouble, due to the fact that fan leaves act as the solar panels collecting light energy. It's your call if you wanna trim off a lil bit of damage, Id probably leave it, maybe mist it when it goes to dark time so it gets direct hydration. If you take the measures I suggested your plant will probably live till harvest, however degraded the yield may be comparitively. Just my two cents man, good luck to you. ~ BCbuddy