Help diagnose problem - pictures for reference

First time with a grow box....and it's been a long time since I even grew plants in soil.. That said. Picked up these plants last week and put them into my hydro setup after having run it for a week with nothing in it to make sure it's all functioning properly. They had roots started and did very well first four days. Temperature is at 87 degrees and 47% humidity. If I'm doing the PH correctly, it looks like urine color. My visual guage reference looks like it's about 5.5. Then two days ago they started yellowing between veins. By other pics on web looked like nutrient deficiency. I mixed up the initial batch of nutrients for a transplant stage. Since they had roots and were already three inch plants when I received them (cloned in rock wool) I thought maybe I should have started them in the vegetative stage mixture instead with higher nutrient content. I mixed that up about 12 hours ago. (note: I also had the first batch of water coming right up under the cups. I have left more space under the bottom of the cups this time.) Seems like a couple of them are a little better but a couple look like they're dying. I took pics of leafs and roots too. I love these little guys and need to figure it out.

shouldnt the lower portion of the roots be submerged in the water ? and yh they look hungry , N .
But take what i say like a grain of salt , im quite a nub XD . let s wait for the big guys opinion

Don't know much about hydro, but I don't think the roots are supposed to be in the water, they should be getting "splashed" by the bubbling...drooping in soil like that means they're over watered....and it looks like a Mag def, if they were in soil...good luck

And by the way, welcome to RIU

Thanks Riknstein and Happy Dragon. I took the pic of the roots with the tray lifted to show the condition of the roots. The 'manual' suggested the water be very near but not touching the cups until roots establish then lower the water level some but it doesn't say how much. I'll try to find out about the roots not being in the water. There's about a 3/4" gap from water surface to cups now but the lower part of the roots are submerged. I'm running the nutrient solution on a 3 hour off 15 min on schedule.

I don't know too much about hydro either..however I do know that, hydro ph should be around 5.8-6.3. I agree with it manifesting as a Mg deficiency as well. I also believe that the reason it is showing signs of deficiency is because of the color of your roots, as they look a little sick. you def need to find out the root situation, so don't add any more nutes until you figure that out or they will die for sure. I like your setup so I hope u get it figured out. Good luck to ya!

Thanks bobswizzle. Our PH is good. Trying to find out about the root situation too. I didn't think they looked great either. Soon as I find out will post for others.

Roots in the water is no problem. You have air stones right? They are usually white unless you are using some brown nutes. If yours are slimy then you are getting that reservoir slime that I read about but haven't seen yet caused by res temp too high. Your ph sounds fine to me too. I think the 87F is a problem.

hey guy

u are a DWC........this means the plants are in water and air is coming up into the roots.............if u do not have them in the water(about inch/inch and half)they are straving

the splash method is a whole other set up they come with spraier system to keep the roots wet

Yes, I have stones. Roots haven't been slimy yet, but will need to check them in a bit. Our nute water is a yellowish when fresh. The grower that set us up has his entire grow house at 97 degrees all the time. He's hydro but they're open in the house. He told us temp ok. (Course we are in the south, very hot here summers--that's why we wanted to do it indoors) But, maybe he wasn't taking into consideration that ours are in a grow box. We have a fan on it but it will get up to low 90s box temp. Not sure what to do to keep temp lower in res.

Thanks for the clarification of dwc justugh.