What’s wrong in my flower room?

[Delta9Med]

I noticed a few leaves that looked like this in my flower room and I need help diagnosing the issue.

Some parameters for reference:

Lighting
Ion 720 led

Temp/Humidity
74 Degrees/50% RH
(Night temps are 64)

CO2
1250-1500 ppm

70/30 coco/perlite mix in 5 gallon pots

Remo Nutrients mixed to 2.2 EC

fertigation every 5 hours with 20% runoff at the last watering each day

pH 6.5

 

[Phill]

Burnt I measure in ppm but ec seems high to me height of light? all your perimeters are off temps to low for that amount of co2 my opinion 1200 should be max ph is high should be 5.8 to 6.5 I consider coco in line of hydro so I’d drop that vpd chart would read something like 85 room temp 80 leaf temp humidity 60early flower late 50-55 just my opinion

 

[theNedster]

I think it's light stress. Is this worse toward the tops? Can you dim just a touch and see if your new growth still displays this?

 

[Delta9Med]

Burnt I measure in ppm but ec seems high to me height of light? all your perimeters are off temps to low for that amount of co2 my opinion 1200 should be max ph is high should be 5.8 to 6.5 I consider coco in line of hydro so I’d drop that vpd chart would read something like 85 room temp 80 leaf temp humidity 60early flower late 50-55 just my opinion

This is an older post but I seemed to have dialed in the issue. I dimmed the light about 5% and brought the EC down to 1.6 and the plants look healthier overall. I also brought my ph down to 6.0 gradually. What do you mean by drop the vpd chart? Does it not apply when growing in coco? I assumed plant transpiration is plant transpiration no matter the medium they’re in?
The only thing I didn’t change right away was the c02 but as of last week I’m running it at 1200ppm. Thanks for the reply!