Need help with a deficiency

Hi hope all is well everybody.
Currently have a few plants that is showing signs of deficiency, I believe it is zinic?but before the deficiency I notice some leaves curling downward so I flushed out the rockwool.
Trying to correct the bad start.
Ppm 400-500
DE MH 1000W
Nutrient advance Grow A & B

Your plants look fine. What makes you feel they are deficient in Zinc?

Because the center of the growth seen light yellow. Or is it me . Looks off

Sometimes when a plant is on the shorter side of Nitrogen, the initial growth at the top of the plant will be a little yellowish in color. It should however, green up as the growth matures. I don't think I'd go screwing with much; your plants look pretty darn good.