Please help identify this deficiency-image included

[Agen36]

This is an image of a fan leaf about 2/3's of the way up an 18" indoor plant grown from bag seed, roughly 60 days old. It has an obvious problem and I was hoping an eye more experienced than mine could identify it and suggest a cure.

The leafs are dry and brittle, curled and discolored.

View image in gallery​

 

[GigaGrew]

looks like it could be a late stage potassium deficiecy but doesnt have the pale green symtoms.

its either a lock out casing a false diagnostic or might be micro's

check PH and double check its not getting TOO MUCH of something and causing lock out.

i would reccomend checking your nute regime for this stage of development and flushing and re nuting making sure you got all the micro's in there and not just the macros