pic 1,2,3,4 = nitrogen deficiency; lower leaves yellowing and dieing from the tips, starts from the base and crawls up the plant. feed with 1/2 strength nutes. what are you using for nutes?
pic 5 = healthy, that little bright spot at the new growth is telling you its eating some nutes and growing.
plants grow fastest with half strength nutes. full strength and 1/4 strength give off equal results, small and sad. also dont cut off the yellow, the yellow is still doing photosynthesis, yellow is the secondary pigment color, purple is the third. the plant will let the leaf die if it has no need for it, or if it needs to eat that leaves stored nitrogen.
