Be careful. Too-green leaves = too much food. Slight lightening of high ridges on leaves = too much light for the food given and/or too little food. Err on the side of too little, because too little won't injure plants the way too much will. Best is to get several opinions.
I have 4 plants total, but they are 2wks apart flowering and all on same system….a pain to start, was all over the place nute wise to correct it u will go through short periods where they all don’t look great. How long as this been like this?
With multiple plants in a shared loop Style RDWC, you will always have issues with the first one and last one to the control bucket. Since it appears to me you have a two site, it makes sense the first one is doing well and the last one will always continue to have a deficiency until you figure out what it is. Judging by the leaves, drop in some calmag and silica. I usually have to over bored those two things in my 4 site to fix the same leave issues you are having....... shit part about a looped RDWC vs a fallponics system, is that the more buckets in a row you have, the less and less nutes the other plants get going down the line....... look at these, my first I e is the front right and the last is the rear right, the front right looked like hell as well, this photo was take after I got back on track...... the rear right took forever to come back and is finally after 2 weeks. Now for the left two. They haven’t had any issues as you can tell especially the front left....