On week 7, One plants chugging along and the others looking a little unhappy. Magnisium? I was thinking flushing with a tea or something and foliar feeding some extra magnesium with a tea and 1/8th nutes solution?
Rockwool 1100ppm feeds every 35 minutes using drippers. Allowing 75-80% est dryout overnight. Runoff after 3-4 hours of feeding to help flush. 1300ppm co2, 83F 800-1100 ppfd and around 72F at lights off,
a little lower than what you're using now. don't foliar feed. this plant usually discolors late in flower and dies, but looks like yours are dying a little faster. rockwool holds nutrients. your ppm is probably too high even though you're using co2. hang in there.