You're fine buddy, but way to stay on them hoes like white on rice! I had some heat stress problems in my current grow... you can view it in the basic growing area if you would like.

Also the yellowing leave, it appears that's at the bottom of the plant which is natural, I don't personally see a N diff. at all... it's natural you will need to take some yellowing leaves off. They look healthy. I had a N problem last time and you will know it when you see it, entire leaves towards the top of the plant will start to look pale and then change to yellow... I think you're doing just fine - keep up the good work