PLEASE HELP!! Yellow and Curling Leaves during flowering Pics attached

I'm in my 5th week (the strain is 8-9 weeks in total for harvest) of flowering and I am experiencing some yellow/curling/dying looking leaves. I have done a lot of research and can't for sure pin point exactly what my problem is PLEASE HELP! I am not sure if I have a deficiency, nute burn, or if my plants are just starting to go through their natural process of dying, where the plants are just absorbing Nitrogen through their leaves. Pictures attached.


Ventilation Good (240 cfm in, 400 cfm out, 1 isolating fan and 1 normal fan in 3 x 4 room)
Temperature at top of canopy 80 F
PH of water/feeding 6.4
A little dry around 40% humidity

Are u still using nutes?

Looks like a problem with the light because inner leaves OK and nice and green. See if you get the spots at the top of the plant where one leaf partially covers another. Look at the covered part and if it's green too much light could be the issue or a combination of light/nute.

He could be right i just saw the burned tips it looks like the light got too close or if ur using veg nutes for it the plant wouldnt need as much nitrogen in its flowering stage and it can burn the leaves but if the bottom of the plant is fine its probably the light

You guys might be right the plant shown is 15 inches away from a 600 watt bulb, however my one other plant with the similar problems isn't directly under the hood and its leaves that are farthest away from the bulb are yellow but the other leaves closer to the light are not (those leaves are fine) and I also have other plants (different strain though) that are closer to the light than this plant that are fine. I am gonna raise the lights to see if that helps regardless if it is a nute problem.

However if it is a nute problem, what kind might you be thinking? A deficiency or burn? If you are thinking burn I will flush them immediately. If deficiency what kind would you think? I was thinking they might need some cal/mg

FYI I was thinking of doing a few more feedings before flushing for harvest (I have sledgehammer so I can flush I 10 days), and my last feeding with Nitrogen was about 2 weeks ago

I moved the lights up and reduced the ballast to 75% and the plants continued to get worst. Is it nute burn?? Please Help!

Anybody have any advise as to whether this is a deficiency, nute burn, or just nature problem? The problem is continuing to worsen even though I have raised the lights (temperature a top of canopy is 76 degerees F). Also I flushed the plant 2 days ago