Yellowing advice!

[CapnCannabis]

I have a gut feeling this is some sort of a nute lock out but have you tried dimming your lights a touch?Only reason I say something is because I just ran into a yellowing problem not this severe but it was noticeable and I had my lights on 50% I dimmed it back down to 30% and my plant started going all green again now it’s the best plant in my tent for growth.Might help you a bit