Leaves curling upward

So I noticed the new shoots at the top of the biggest plant started to look burnt a few days ago. It was really hot so I just assumed they got a little dehydrated. Now the problem seems to be progressing to all the new growth.

I have another plant in the same tray and it isn't having any problems. Im 10 days into flower and its my biggest plant, please help

Bump for my sad plant

Whats your pH and ppm run off looks like nute burn. Might try flushing her soil out.

It's not a nute burn, its heat burn. You fried 'em good.

Thats wierd that it would be heat. no other plants are burnt and its top is a solid foot further away from the light than the plant in the same tray. I went ahead and swapped out 10 of the 15 gallons in the res and im hoping for the best. PH was at 5.7 but I dont have a PPM meter, guess I should probably invest in one.

it could also be due to low humidity.

you said it was the biggest plant right?? thats why its deffo heat problem the leaves curling up is a 100% due to heat.

Thanks for the feedback everyone. Its a nice cool 70 Degrees today and the AC is working so I hope whatever is hurting it is taken care of. Ill keep you posted.

It does look like the plant got too close to the light and is burnt... I've done it and it looks very similar, if that's not the issue... as someone mentioned... what's RH? Don't know if that's the problem.. but may be a variable to exclude as a possibility.