Micro nutrients. … 
@bryan , best before doing anything i would recommend you posting a pict . but if you want o do diff , you mite get a nutrient solution that use’s micro in the formula .
Hammer.
To answer your question for iron:
FeEDTA, FeDTPA, or FeEDDHA
If used, I recommend FeEDDHA.
https://www.amazon.com/Grow-More-6546-Chelate-1-Pound/dp/B00BWE2CUE/ref=sr_1_1?tag=greenrel-20
“But” are you sure it’s iron? Its unusual to be iron deficient if you’re using a premix hydro solution set as directed.
1 Like
Seems to be a lot worse with rapid growth
@Hammer Here is the pic.