Bam, look at that. First true set of leaves too. You want to start feeding nutes @ 1/8 strength very soon as there is no nutrients available in that hydroponic setup. Just a very basic veg nute or a broad spectrum "feed" (think Liquid Karma). Again, VERY little - like, take an eye dropper and put 4-5 drops per gallon of water.
What nute line are you using?
Let us know, also - how are you monitoring PH? You want to start keeping an eye on it now because problems won't show for awhile unless the pH is EXTREMELY acidic or EXTREMELY alkaline, but in about 2-3 weeks you'll start seeing pH issues if you don't start monitoring it now.
You're on your way brother, keep it simple and take it slow - don't rush anything and you'll be greatly rewarded!