new GROWTH COMING SIDES ARE YELLOW and stunted PICS

I am not sure if this was an insect problem like fungus gnats that caused this on all of my plants or if it is a soil issue. I checked pH and it seems to be in range but, I am a first time grower so I don't want to make a mistake.:mad: I have been using rain water I was getting off my gutters which is good to use than tap.

this one had a gnat issue for sure

hy there mate i have the same problem but im at a loss too. my ph is fine and im using good nutes???

i use RO water. flush once ever 4-5 days at the moment....

maybe the water were using is too pure and doesnt have enough mag or cal???