LED Light Burn

[Grow17]

My plant tops are 19" from my 600 watt LED.
This is the 2nd grow that it's happened with.
I can possibly move the light up another inch, but not sure that's going to help.
The only other thing that I'm not sure could be a factor is that my cooling system has been wacky and I've caught the light off temps being in the low 60s while light on is a fairly steady 70.

 

[luvinthebudz]

almost looks like a little nute burn too..

 

[Grow17]

almost looks like a little nute burn too..

I mix my nutes on the low side.
Right now I'm on FF's week 7 schedule.
I was advised to try shade screen, so I added a 30% screen yesterday.
Lights come on in 15 minutes so we'll see if that worked, as I cut off most of the damaged leaves yesterday.

 

[dunkindabs]

Try flushing it and start with less nutrients, and see if that helps them recover.

 

[Grow17]

I just checked, seems like the screen has helped, but my other grow has the same thing happening along with yellow leaves.
Unfortunately I just feed them yesterday, so there is a good chance it's nutes.
I have to wait until the soil drys before I flush correct ?