I see some issues.. Give us a rundown of your grow.. Nutes, Ph all that stuff..
Absofreakinglutely.If you're using Ro or distilled.. You need Cal/Mag..
Absofreakinglutely.
When I use RO water, seedlings stall and die. Everything older has issues. So it's straight from the tap at 7PH for me (I'm on a well).