it looks K related,... was there a pH hiccup recently? K is more tricky than other for diagnosis sometimes,.. the burning of "teeth" tips and along the margins happens with both defc. and toxicity,... I see tip burn on other leaves, which makes me lean toward this being a over-dosing things, .. that Kool Bloom is fierce stuff! What are the ppm/EC in there, and how much of it is the KoolBloom?