Stumped

I’m just going to try 1 fix at a time here and go from there.

flushed the whole room out
raised temps
lowered humidity
lowered feed EC
lowered lights back down to 24” at 960w total
upped feed time to 2 min 3 times a day instead of 1 min 4 times a day (keeping a close eye on dry out)

It hasn’t gotten worse since so there’s that lol

bk78 said:

It hasn’t gotten worse since so there’s that lol

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If your doing that in a 4x8 24” Is a little to close Numb it to 32” above the canopy because if yo it doing qbs they are pretty strong

bk78 said:

So I just re read that link you posted again, all 5 of those scenarios listed all have cupping leaves as symptoms. And it could be 4 out of the 5 listed (heat was exclude)

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Indeed but you have to exclude ones that don't fit.

Which really only you have a firm grasp of

High ppm is secondary(in this case) to not enough moisture/ watering/runoff. If they're transpiring without enough moisture to the roots, leaf margins almost always turn up, ime.

If given enough cal in coco, i believe you're experiencing an antagonistic effect of accumulated salts, due to dry medium, which you've discovered

bk78 said:

It hasn’t gotten worse since so there’s that lol

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The margins don't always correct themselves, depending on the severity of course.

Nice grow btw. Like your setup.

dangledo said:

The margins don't always correct themselves, depending on the severity of course.

Nice grow btw. Like your setup.

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Thanks man! And thanks for that link as well I have saved it for future reference.