Hey again

Room: 77deg F/65%rh
DWC, 5 gal. Buckets, 15 L water
Plants: all autoflower, various stages of development, all flowering.
Nutrient: HOG 3 part (grow/micro/bloom) basically same as general hydroponics, but with a little bit higher concentrations I think, Feed at about 3/4 strength of their chart
Additionally: Regent-a-Root @ 1ml/L
Hygrozyme@ 2 ml/L
H²O²@1ml/L(every 3 days)
PH 6.0-6.5 (usually drifts up)
EC .9-1.3 (usually drifts down)
Well water is filtered then uv treated. Comes out of tap about 140ppm/ph 9

Skunk:
2 weeks into flower, still stretching a bit

Jack Herer:
Maybe 30 day flower done stretching




Unknown Genetics:
About 60 days into flower (more to go)




Also this one seems to have really dark leaves (N tox?) Compared to the one underneath it


Any help would be greatly appreciated. Seems like all my plants end up with this issue, early to mid flower and am never able to resolve.