They looked good before I moved them

Before

After


I have included a before and after of my plants. I had the plants in some sort of growing tray. It also has a plastic lid that allows for the adjustment of airflow. All the plants looked very healthy before I moved them to my DWC container. The roots were exposed but werent long enough to touch the water. I have manually spraying the play with a water bottle. Also I have poured water down in the contained but over the plant so I don't believe the plant is dry.

Those domes you speak of are not for seeds. Well they are, but not for how long you had them in there, a month? No. Trying to be a Dick but, no they didnt look good before. They were stretching like Mad and the roots were exposed to light. Super Thrive. No nutes. Give them light far enough away so they actually like it. And don't go over a few days in those cubes next time. Place them strait into the DWC

Don't know anything about DWC so don't know what you did to kill them, but that's what it looks like has happened.

I'm new to DWC,

I'd say they need water. When mine are young/small I fill my 5gl DWC bucket up so the roots are are wet. After roots break through the net pot I lower the water level below the net pot.

Just a thought.

Good luck!