New growth is light green – seems like Nitrogen deficiency or maybe light-burn? It's been getting slowly worse. Water ph is 6.7, Fox Farms nutes, AC Infinity 4x2 w/ 200w lights @ 18" on 80% power.
Make more light distance like go for 26inch and 100%light it help your plant strech too I belive its early stage light stress then hopefully will sort it in couple days
This is not overwatering. I think this is normal. My new leaves are also quite bright, the older ones are kinda dark green. Let me know if you find out anything else! Good luck :)