Burn or Def ?

This is happening from the bottom up. Is it lockout, deficiency, or burn ?

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I don't think its burn, burns are usually a bit crispier on the tips.
Looks like nitrogen deficiency, could be caused by not enough nutes, or too much.
A lockout IS a deficiency, as it 'locks out' the uptake of the nutrients.
What's your medium, and how much, and what have you been feeding?

Looks like Nitrogen deficiency

Deficiency. https://www.icmag.com/ic/showthread.php?t=231387
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