All these deficiency's can look similar, you have to go by what youve fed to rule things out.So say you havent fed much then could be a K deficiency or say youve been giving it calmag and heavy nutes then maybe its a toxicity of something blocking something else.
Your right I got the fox farm trio I just started feeding to I waited till this week it's in the middle of week 5 I started feeding a week ago I thought it was light feed but it's only my second grow so still learning thank you I'm in prohibition land so there's no one to ask here