Color issues

I have two sets of plants and 2 grow rooms, and I'm only having problems with one. when the seeds first sprouted the were yellow, an easy fix so i thought. its been about a week and i can't seem to get them green. I've been growing for some time now but this my first year indoors. some one has to have the answer. but time is an issues i have a feeling that if i don't correct this i'll only have one set of plants.

What method are you using to grow the plants? I mean, soil or hydro? Yellow sprouts .... a new one on me.

Vi

You ph testing your water. How hot is your grow room? What kind of light?

the room temp is 70-76 and I'm growing in soil. and im useing Flourescent lights.I heard something about potassium. there geting some color back i put them in the window cell just for all natural light