Brown Spots

Hey everyone. I was wondering if someone could inform me on what is going on with this plant. From my research I am guessing it is a calcium issue. Is this what everyone else would believe as well? I appreciate the feedback.

This plant is indoors with coco perlite mix 70/30. Feeding once a day with lucas formula + calmag. the light cycle is 24/0. This plant is a northern lights auto. This plant has just started its 5th week from seed.

Im not experiencied but would agree with you due to the kind of spots while checking another pictures on Internet.

Please add more data so you can get more help: medium, nutrients, etc.

I would guess magnesium deficiency, but I'm still learning. Maybe try some cal-mag.

edited my post with some additional information of grow. Thanks everyone.