Brown spots on leaves

[LittleBadger]

Brown spots on leaves - spreading to other plants fast.
Think different in soil under led.
9 weeks old.

What is it ? Fungus?View attachment 171273

 

[alley_walker]

Is there anyway to get a pic away from the LED? Its throwing the colors off. But right now it looks like classic nute burn with a mag def.

 

[LittleBadger]

not possible to get another photo just now.
the leaves are a good dark green color - the spots are light brown,or yellowish brown

 

[User K]

Calcium def mate, looks similar to one of my plants. Happend late into flower.