HELP! root problems? wilting plant

[ausglove]

Hello, I have 3 plants in dwc, all three are drooping and have a stunted growth I can't seem to figure out why. Everything leads me to believe it's a root problem but I have no idea how to fix it.
Relative humidity in the room is 50-60%
Room temp 70-80 degrees
No light leaks that I can find in the totes
Water temp is 68-73 degrees
I'm using botanicare kind nutes (first time using those)
Ppm is around 600
pH is always between 5.8 and 6.3
Here are some pics of the plants and their roots. If anyone has any tips that would be greatly appreciated 😊

 

[vostok]

indicative of not enough 02 for the given size


bigass air pump please!

 

[ausglove]

There are two airstones bubbling water pretty good inside. The totes are shallow though, maybe not enough water for the oxygen to move through? These ones are not top fed and have just a small pump inside, maybe I should get taller totes and get a bigger pump to circulate inside the tote? Make sure all the water gets some oxygen