I have 2 plants that are the same ...they share everything....same dirt...they get the same nuts...the same water...are in the same tent under a 600w HPS...they are in wk5 now and one of them has a lot of yellow leaves with some purplish brown between the veins while the other does not. looking at everything on line... it seems like its a nitrogen deficiency ...bt cant figure out why they both are not doing this...I am crazy about measuring my fox farms nutrients and I PH my water every time before I feed or water!! driving me insane my temps are between 78 - 80 F ...and my humidity is between 40 - 50. HELP!!!!!

I have some pics if they will help