Ch33cHanswered grow question 4 years ago Could just be a Cal/Mag problem with brown roots. I have grown plants in hydro that have not required calm/mag and there has been others that yellow up quite quickly without. But another sign of brown roots other than root rot is calmag.
If it is root rot then good chance it has occurred due to your tempature problems. I choose to grow with Coco rather than dwc because i would struggle with my water temps.