Light burn for sure?

[Dbdigger]

I have gone through all of the forums and plant problem pages. I think this is Light burn, but we can't understand why. Light is all the way up to the top of the tent, and still only at 25% power! LED 300 watt.
These are in week 3 of Flower. 2 Bruce Banner 2 OG mush. The BB on the back left is showing Burt tips and edges and overall much lighter leaves versus last week's pictures.
We water about every 3 days, PH run off has been between 5.7-6.3 on all plants. If it is light burn, how do we correct if the light is already all the way up and only at 25 %, 12/12 schedule. Thanks everyone.

[OldManGrower]

I do not claim a high level of expertise but I do not see any light burn. Raise your PH to 6.7 and see what happens. The low PH will cause poor mineral uptake.

[Farmbuck]

I agreed with OldManGrower

[Xena]

I’m no expert either but all I see is a pretty nice looking grow.

[billyboy]

More light and more food

[Rwise]

I agree, bring the PH up to ~6.7

[Dbdigger]

Thank you for your input everyone, we will up the PH and see what happens. But need a little help getting there. We currently use Distilled water because our tap has super high levels of iron, and we have A RO unit on order. So even if it's a water only day, (just adding Cal Mag) it seems to take so much PH up to get to that sweet spot desired of PH. So if My last run off was at 6.2, should I be putting In a higher PH of like 7?

[ZigZag]

Not light burn. Looks like slight nutrient burn because plants are too healthy to be deficiency. But its slight enough I don't think you need a full flush. I would water with PH 5.8- 6.5 with half strength nutrients and water until 25% runoff for 3-4 days in a row (as long as you have a medium that drains well, quickly)- Then no water for a few days and then resume with normal nutrients and water. Looks nice, you'll be fine.