Sup Growgood, I stuck this in its own thread so people would see it. Just from the description, it sounds like an iron deficiency, but you should fill out the troubleshooting form and if possible post a pic. If you can't upload pics, you can put one up as your profile picture until you have more posts.
Iron def is often actually a lockout, so why don't you test the runoff pH of your soil and report back what you get.