Dead Plant?

This is root problems, probably due to mold or something , you can get rid of most of the problem if you use something like hydrocloric acid diluted a lot (think of how folk use it for the flush) then add hydroguard again... sometimes bad bacteria can get past it, simple as that i'm afraid. Hope this helps ! 🚀

tienes un bloqueo de nutrientes, haz un lavado de raíces. Y mira la EC de drenaje

Looks to me like a root pathogen..

Not an expert at all but kinda looks like a lot of heat and wind from fan