sir_isOanswered grow question 4 years ago Yeah as B4rns and InspireMe says, looks like you got some form of toxicity, nitro especially, related pH issues and associated lockout/deficiency.
Flush (at least to some extent), definitely lower your nitro (probably not only) inputs....and use some buffering stuff (calcium, magnesium, potassium)...and some general elements, microelements.