Discoloration and burnt tips

[AntoMaria7]

Hi! So this is my first grow, so far so good. Now i am in the second week since i switched to 12/12 and on one of the plants(out of three) i noticed some discoloration and burnt tips. This is happening with 3-4 leaves but i don’t want to advance. Soo, what may be the reason?? Thanks in advance
The last photo is with them all
Btw its not a blurple or how it’s called, between normal warm light bulbs ia one full spectrum infrared or smth(it’s pink), it was the first one i bought and i left it because the girls seem to love it, under it is where it is most developed

 

[HydroKid239]

Maybe dial back on the ferts just a tad, but they look ok. No serious damage that would cause your leaves not to photosynthesize.

 

[AntoMaria7]

Maybe dial back on the ferts just a tad, but they look ok. No serious damage that would cause your leaves not to photosynthesize.

I was thinking the same but i’m feeding them like before that’s why i’m worriedhaven’t switched to flower nutes yet. Only nutes can be the problem? I also changed the lights a couple days ago with more powerful ones, also from white->warm light, can this be the cause also?

 

[HydroKid239]

I was thinking the same but i’m feeding them like before that’s why i’m worriedhaven’t switched to flower nutes yet. Only nutes can be the problem? I also changed the lights a couple days ago with more powerful ones, also from white->warm light, can this be the cause also?

I do see some light stress. So it’s possible. NOT all the tips are burnt. Some are cupping tho.