Dark leaves, top ones burnt, curled down

Hey everyone-

First timer here. I am in wk 6 flowering. The leaves are a VERY dark green, the top leaves first became crispy, then burnt. Even the sugar leaves are starting to dry up. Ph is 6.0-6.5 according to water test (closer to 6.0). Currently watering once every other day, with feedings every other watering with Tiger Bloom and molassas. They are in 8" pots, Scots premixed. The bottom of the plant is fine, but it appears to be moving down. Not Mg Def., and leaves are definitively curled DOWN (fingerlike). Also,t he top fan leaves are shrunken looking and curled (very datk, again....). Have stopped nutes and am running straight water (Ph is 6.0).

Any ideas? Heat /ventilation is not an issue, entire room and A/C dedicated.

Thanks!

A plant will tend to show signs of dying as its cycle of life comes near to an end.8 inch pots are kinda small unless you went 12/12 pretty fats when plant was still small.Lights arent to close? Air moving at plant tops via a fan?Any pics?

Will post pics later. Flushed last night. Rather yellow water. Running straight water for now. I think some of the damage is heat related, as the LST restraints slipped for an hours or so - nothing bad, but the new growth is still exhibiting the same symptoms, and it appears to be moving down the plant. The EXTREME lower leaves are also burnt, but are splotchy yellow /green instead of the dark green / brown.

Thanks