Pineapple Express help!

Pretty sure this is a magnesium deficiency but not 100% can anyone help? All the new growth at the top is really yellow and getting brown spots on them. Really don’t look healthy at the minute. Growing in clay pebbles . Ph is around 6.0. Using vita link hydro a&b.

What week are you in my dude? do you have any preventative pest control measures? Are you using the Hydro Max? Hard or soft? How much are you using? Some of the brown spots and weird lookin growth look like pest related issues, and they look generally under fed with some mag deficiency lookin shit too, which would lead me to believe there’s a problem with uptake of minerals that should be present.

I’m in week 4 of veg mate. It’s only the one plant that I’m having issue with. I’m using the hydro max . Im use 2ml per litre and I’m putting in 60 litres in my tank. Would it solve the issue if I flush the one plant with ph plain water?