weak seedlings need Help

[Pinkstardust]

One started leaning over. Had to prop it up. Then the rockwool was too wet and I transplanted them into bigger pots and drier rockwool. one has a slight yellowing on the inner leaves. What helps?
Will try to get a pic in here

 

[Dank one]

lights could be to high, to much/not enough nutrient. wrong nutrient. or just a bad plant. Honestly I start with on average 20 plants and end up with 4 by the time I can sex. Also its hard to drown a hydro plant.