It looks like nitrogen deficiency,but I’m not sure, there’s a section on the site about feeding
I would start by Looking at my runoff numbers PH, PPM
And make adjustments if needed. If possible fill out the support ticket That will create more input.
Yellowing from down can get a little tricky. That can be a micronutrient issue or handful of other things. Have you been monitoring ph and ppm in and out?
maybe this will help