WTH is going on with these?!

Im growing 7 plants in 1 room under 1 600w hps light with a 125 fan.
All 7 are cuttings from a black widow, grown in coco and fed (what i was told by my "teacher") 40ml a + 40ml b per 10l water. Theyre currently at the end of week 3 and after a few teething problems seemed to be doing fine.
Tuesday this week I noticed major curl on the leaves over night. SO after hours of research decided it must be nitrogen toxicity and nutrient burn. However, none of the pictures resemble anything like mine. I dont think it has any blue genetics so it cant really be that. Since tuesday Ive not fed them at all and started flushing them through with water.
I really feel like a bumbling idiot and that the so-called experts helping me are blowing smoke up their own!!
Is this Nitrogen toxicity???
Could it be the light is too close at 3ft away?

hmmmm, I just fed my plant N in miracle grow n the curling in one of the pictures resemble that of a N toxicity like mine. not 100 percent sure but I'll be looking for a fix aswell. I think the Orange spots are something different. def a little nute burn on your tips

Too much N.
You should not stop other nutes out right.
Just don't add N for a while.
And that plant has a lot of N to burn through before you see recovery of leaf, and the plant as a whole.
I'd wait until recovery and new growth are under way before flowering as leaves affected by N toxicity can some times just die .

EDIT
What are your temps and RH ?
Looking at the pics again , I'm not so sure it's just nutes alone

Poor night time temps ...see the red tinge

clawing due to excessive nute

too small a pot

too poor or low ventilation

not enough study required


nice fingerprints for my collection ...thanks Ru?