Browning leaves please help!!!

I'm growing in coco. It's about the 5th week of flower and specifically only top leaves are starting to brown and die. It begins with brown spots on the tips of the top leaves and eventually speads to the rest of the leaf. I usually keep ph between 5.8 and 6.2. I'm using the gh flora series using their "medium" feed chart and have been giving it a Feed ec of about 1.6 to 1.9. Run off has been coming out high at about 2.0+. I use an automatic watering system with a reservoir, not sure if that is an issue. I also thought it was a calmag issue so went from 2.5ml p/gal of calmag to 5ml p/gal but it seems to have no effect. It's an autoflower strain of skywalker haze. My plants are pretty close to my led light but it doesnt look like light burn to me but maybe I'm wrong. My best guess would be to lower my feed ec since it seems to have been coming out consistently higher which I usually flush out. Thanks for any help

they look very close to the light, 3-5 inches? Any air movement in there? what's your temps and rh like?

I am not experienced with autos but as far as I am aware they usually tend to be more sensitive to feed rates compared to most photos. It looks like several issues going on. did you check for any bugs?

They are pretty close to the light. But the temp at the canopy stays about 70 to 75 and rh about 40 to 55. I have a large fan under the canopy and an ac ventilation unit going 24/7. I have not seen any bugs

Kinda looks like a couple issues. Time to narrow down a few things. Your temps look good so does your feed schedule but you need to know the surface temperature of the leaves themselves because you may be giving the plants too much light. What are you doing for air movement? Intake/exhaust?

I keep my thermometer close to the top of the canopy and it usually stays 70 to 75. I have a large fan at the base of the plant that blows up, then i have a ventilation system that draws air from the top. It's a 6inch vivosun ac with 390cfm which I think k is more than enough for my tent size of 2x2x5

What I mean is the intensity of your light may be too much for the plant to use for photosynthesis so its actually causing it to stress and mimick other issues.

My light has a dimmer switch that may be useful for that. I also know there are some phone apps that can measure the light intensity but not sure of they are recommended

I believe others have used the Photone app.. That being said we know your light is too close at just a few inches from the tops. Also at this point dimming it would not really be a sufficient option. Honestly you let it veg too long and it is outgrowing the tent, you can try super cropping but it still seems like space will be an issue.

I also think you are over feeding or have some form of lockout or ph issue causing the leaf issues.. when did all this start showing up?

@Herb & Suds you mind taking a look and giving your opinion here

It's def too big for the tent haha. But this was an autoflower so I didn't have much choice with veg time. I thought autos would be smaller haha. And this all started a couple weeks ago. It may have something to do with my new automatic watering system but I'm pretty good about checking the ec and ph (typically 6.2) of my reservoir. My guess was over feeding as well since my ec keeps creeping back up to 2.0+ while I feed it around 1.6 to 1.7. This is my suspicion because I've heard that autoflowers typically don't require as much fertilizer. And I fertigate twice a day and give enough for ample run off. Could increased fertigations help?