Dryed out plant in hydro

Thank you for the answers everyone. I think oxygen lack sounds most plausibel do to many factors i do though use a little airpump already but i believe for serveral reasons it might not be enough.

Something fundamentally going wrong here.. I’d pull up that drip ring and inspect thoroughly.

test pH? maybe that rez has soemthign growing in it? what is EC? if above 1.3-1.5, try lowering. is it possible you mis-measured soemthing? i once mixed up a couple gallons for a water tank, but i accidentally did 1gal worth of nutes... after a coupel irrigations i saw the effects, lol.. oops, thankfully it was on light side and not a double dose.

It may have caught a phytotoxicity due to differing genetics from the rest of the plants. Some phenotypes just aren't as hardy as others from the same genome. I hope this helps.

Maybe too much heat