Yellowing on seedlings, first timer help

Hi I'm in week two and and a half and from placing the germinated seed in my medium which is mother earth terracraft. Using a mars hydro 2000w and have been seeing so many different things opposed to height and dimming. I have it almost completely dimmed at about 80% 32 inches from the seedlings.



I do realize I was overwatering a bit at the start and it was stunting growth for a while but my issue is here where my leaves are were starting to become dryer and crispy so I lowered the brightness of the light a bit

Can anyone identify why my leave is starting to turn yellow ? And possibly any other things that may be wrong with my plants

You sure you were overwatering? Medium looks bone dry. You can let it completely dry out every once in a while but at this age you wanna keep the Medium moist.

What is that bark chips? That's root rot setting in...especially if you over watered....it cant take up enough nutrients it needs