Yup raise the light, can’t undertand if your stem is purple or is the light. Maybe you have to give them some extra calmag with led, but not sure, for sure raise or dim a light a little bit. ✌️🏽
Raise your light a few inches just to be safe, if the pale colouring Appears on new Growth you know it’s something more serious a deficiency of some sort which you would have to look into further to diagnose hope this could be a help to you, happy growing pal good luck 👌🏻