Please what is this?

Hello, i have issue with my plant, some leaf have this...

What cause this?


Thank you!

Looks like calcium deficiency

Thank for quick reply, but i use 5ml of calmag every feed.., do i need more?

i use soil and they are 40 day veg

Thank you!

Not sure if this helps, hopefully you can read it.
Maybe Potassium deficiency.

Thanks you!, look like i have magnesum deficiency, maybe my ph is the real issue ... i think is near 7.0 that why they cant take all nutrient...