The clear pot isn’t ideal first off. Every time a root makes it to the edge or the cup the light will kill it off. It looks to ph related but is likely a root issue do to the cup and the media looks very wet. You want the plant to dry out completely between waterings unless you are in coco. In which case you don’t want to let more than the very top dry. If you add perlite or something similar to you media you will increase drainage and root airflow. Also it will let the plant go through it’s wet/dry cycle preventing overwatering in most cases. Hope that helps and happy growing!