Hi:
I've got sprouts just starting to grow their second tier of 'real' leaves.
They look good except that they're starting to look more and more yellow.

I'm using a hydroponic drip system. They're in General Hydroponics Rapid Rooter plugs surrounded with Hydroton clay pellets in net pots.
They are not in standing water.

I'm using Advanced Nutrients Grow-Micro-Bloom and I've got about 1/4 strength in a 5+ gallon reservoir of RO water at 0 PPM (before adding nutrients). I've also got just a tad of Advanced Nutrients Barricade in there to level the Ph.

I'm watering for 15 minutes 3 times a day.

I did have a problem with Ph rising just a bit (not above 6.4) but I think I've got that under control now. It's pretty consistently between 5.5 and 5.9.

What am I doing wrong? How can I get the leaves to green again?

Sounds like nute burn... but you have good drainage. Do what I do when I have a problem ask Skunkushybud or Fdd.

__________________
"I smoke two joints before I smoke two joints then I smoke two more!"

add more nitrogen to your solution...The simplest way would be to piss a little bit in your nuted water.

yeah thats probably nute burn...i would stop and stay off the nutrients until right before flowering stage then start them at about 1/8 strength since youve already had them at 1/4 so early. but i agree with the post before me on asking fdd.

__________________
i cant believe people actually believe that i grow, use, or smoke marijuana...dumbasses

Completely stop any nutes at all for the next 7 weeks?
The PPM now is about 118 now.
Advanced Nutrients recommends a PPM of 800 in the first week of Veg.

How can I ask an individual user (ie. fdd) a question here?

send him a private message...but yeah you defineatly dont want to start using nutes until around 4 weeks in..and since you have already used them id wait longer.

__________________
i cant believe people actually believe that i grow, use, or smoke marijuana...dumbasses

Turns out that fdd only grows in soil.
This is a hydro drip system.
Is anybody here an *expert* with hydro systems?