heat stress or nutrient deficiency?

Hey guys first time posting on here and its my first time growing so here is my story
i got 4 clones from a friend. we had them under some marineland single led fishtank lights for a while about 3 weeks then we bought a 150watt hps light and put them under that now we are having some problems with some stuff just let me know what this is i think its heat stress but if it is something different please let me know thanks!

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looks like heat stress to me.. try to put your lights a little bit away

Yea i agree, looks a bit like heat stress, although, i dont see why it would burn a lower branch before singeing a higher one, so....could be either one mate.