Is it potassium deficiency?

[TryingToDo]

Hello. Its day 21 since it showed its first pistil. And approx. 1 week since it stopped its vertical growth. Its a purple auto haze?
Recently I noticed that old leaves are getting yellowish.
And what do yu think of my plant?
Note:tips caused by nute burn on veg. I mean look at the inner of leaves.

 

[Chris Scorpio]

Lower older leaves are normal at this stage to die off

Are u feeding it bloom nutes?

 

[TryingToDo]

Lower older leaves are normal at this stage to die off

Are u feeding it bloom nutes?

I gave it yesterday very slightly as i had nute burn problem giving it growing nute even though it was just 1/4 strenght