Yellowing of new babies, Help!

My plants are all within a week to a week and a half range. There a lil bit of growth stunt i believe and the leave tips are turning yellow and gettin lil brown spots on them. I've done reading through countless pages and read several different things and opinions. It's a DWC setup and the only thing that's been added to the res is a solution of water, SuperThrive, and a lil H202 thas all be pH'ed. What could my problem be, i'll be putting some pics up for you're viewing pleasure. please help, i'd like for my 1st go round to turn out to be somewhat decent.

Possible Lack Of Nutes...start With Uping Your Nitro.....dbb.
ONE MORE THOUGHT OVER NUTING CAN LOOK THE SAME... CHECK YOUR BASICS
IT IS YOUR CALL PIC'S WILL HELP...PEACE dbb.

get some thrive alive b-1.... i love it...
small bottle with red label THRIVE ALIVE...
I use only that till needs transplanting....

Here are a few pics, sowwie for the quality it's from a camera phone. I'll be gettin my brothers cam in the next couple of days. But these pics, a couple of them are worse these are from like 2 days ago. Like i said it's getting worse. I read somewhere that superthrive shouldnt in the res, that it should be applied to the leaves in a spray bottle, would this be true? But yea, juss take the pics and imagine them a lil worse than they are. They need SOS right now lol

And thanx for the prompt feedback I like that, I'm apart of another forum and I barely get responses to post. pretty sweet