Welcome to the forums...

Couple things. First you want to lower the water level. You want the airstones to create bubbles that burst at the surface and splash tiny amounts of water up towards the net pot. If you submerge all the roots under water they will drown.

Second you want to keep the PH at 5.8. Also if they are still as young as you say then they dont really need nutes yet from my experience. If anything you can use Superthrive or 1/4 strength nutes.

Superthrive worked great for my DWC seedlings... Made their roots explode. Check out my DWC grow log here http://boards.cannabis.com/hydroponi...-grow-log.html

or some others for tips.