Light stress?

Hey everyone,

first grow. running 4 autos in a 3x3 (yeah she’s getting cramped :/). Had a rough start so the girls are all about a week apart. My tallest is in early flower and has started to get some yellowing and brown spots. It seems to be limited to the top/closest to the light. So I’m leaning toward light stress. I’m running two ES 180s and had the second lower for the shorter plants directly under it. Wondering if the side light could have been hitting too hard as it also seems to favor one side.

growing in coco with dry amendments. top dress with green sunshine co. Earth dust boost about 1.5 weeks ago. Water every day, ph around 6.5, she gets about .5 gal each dat and seems to be good with it. I occasionally add cal mag, but it’s 4-0-0 at at one point I was concerned about an N excess, so I’ve laid off. Don’t know for sure but I’m using dechlorinated tap water so I’m assuming it has some amount of Calcium in it.

I’m thinking it’s light stress, but... it’s my first grow, what do I know... Any thoughts would be appreciated.

Not spots like that. Are those red stripes on stems? could be genetic or needs phosphorus
Is this mostly organic? Coco+strong led i have been told you need calmag upto just tsp/gal so it shouldnt add much N.
looks like this https://www.ilovegrowingmarijuana.com/nutrients-deficiency-calcium/ or https://www.ilovegrowingmarijuana.com/marijuana-nutrient-deficiency-phosphorus/
another site to compare https://www.growweedeasy.com/cannabis-plant-problems/calcium-deficiency

Also use a LUX meter or phone no need to guess you can get a ballpark using this converter and it comes close to specs for my wattshine 900 but i used a lux meter, my phone was close though too.

Looks perhaps, like the start of a P shortage and maybe even a little K...good luck friend.

Looks like you could be right, move the lights up a bit, or dim them.

Thank you for the replies everyone. It really does look like a phosphorus deficiency... going to try lowering my ph down around 6.2 when I water tonight and probably do a tea with earth dust boost for tomorrow