Northern Lights[Seedsman]

From before you switch to 12 12, you dont want to do anything to stress her going into flower. Cheers

You want your blue hues to be there during the veg state for flowering you want them red hues to replicate sunset you can use the same light but it may affect your growth, some people use the veg and bloom at the same time the whole way through

The difference in light spectrum is not as important as some people claim they are. I use flowering lights for vegetation all the time. While it may not be 100% the optimal wavelengths, it's not worth buying different lights for veg/bloom in my opinion.

Juste un bon réglage de la distance de lumière pour ne pas les brûler

It’s like a micronutrient def, Zn causes the necrosis on tips of the leaves in a immobile way. Maybe combined with Mn that causes that one in the middle of the leaf. Are u sure to give them enough calmag?