That actually looks like you're beginning to over fert...

the yellow/brown tips are a sure fire sign of nute max out.

Remember that fan leaves will be lost normall throughout the entire grow. Especially into flowering....it's pretty normal and you'll probably lose a good 40% of the major fan leaves by the time you've harvested...this is why we tell people to refrain from pruning fan leaves...as they come off once they've served their purpose anyway.

You don't need to add more nute..

Bob