Potassium ???

[Highroller]

Im new yall.
dont know a thing about forums or how to act.
what i do know is got a problem and have no ideal what is wrong
From the attached picture, i think i might have a potassium problem,,?????
help

 

[homegrown]

How close are your lights? Looks like light burn. Cupping leaves and yellowing tips is a good indicator.