Please help me identify these brown spots!!!!

heya all, my plants are currently on their 2nd day of 12/12 cycle and these brown spots have been appearing on random leaves on the plants. What could cause this??

did you spray the leaves with something?

Nah, never sprayed the leaves with anything at all. Does it look like heat burn?

no idea. Never seen survivable heat burn for myself yet.
are you feeding them some sort of flowering nute already?

EDIT:
heat would damage the tops i would figure, you said it was random though, right? Tops, mids, and bottoms?

looks like some minor nute burn as leaves seem real green but in pic 4, leaf seems brittle?

im sure i had something like that, i put a mix together and didnt check the ph after, it only happened to one of my plants though the weakest one to be fair so maybe the others were rooted enough to pull through, after i did another food mix with the right ph it didnt continue but those couple of leaves were still fkd, plant still growing strong though so maybe your all good?


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Im feeding them nf coco nutrients which uses diffrrent amount for diff stages instead of grow n bloom formulas.

Chubby: yeah they can be on top and at the bottom so i dont think its heatburn. There were alrdy little spots last week but today seems to be more spots than ever.

Thexception: they look brittle cuz they were taken under hps light mate hehe. Leeaves are green n looking good but im just concerned bout the spots n wanna nip any problems in the bud.

always good to be aware of any changes & u r, but u have to access the overall plant health & appearance. At this point I don't believe u have a problem to worry about. If there r more spots all over, post some more pics so maybe we can take another look, because all I see r some good green foliage w/a few minor & likely nute burn spots.

Haha good to hear assuring words. Yeah im gonna chill n just observe them closely these few days. Hopefully its nothing. Cheers guys, appreciate it

Slight nute burn. looks exactly like my plants did and I dropped the ppm down about 150 and the problem stopped.