It looks like root rot or ph. Nutes, medium, ppm, why is the light red, and what do you think that screen will do? I dont get those screens, is it co2 release? If they grow into it um I know that you can not rotate them or supercrop them which is neg. but whats the up side? Are you watering them from the bottom. Here is how I have brought plants like that back, flush heat and humidity. If the roots stop working which is the case dont let the stomas transpire all the water out. No fans and hit em with humidity.
One love c