Well this doesn't really make a good case for the AeroGarden but after some experimenting I found the most likely problem. Although I wrote about it in my tips section, it turns out I am a victim of not taking my own advice. I thought my water was cool enough but apparently it is in fact too warm.
Here is the timeline...
May 2, 2011
Five days in and all but one had sprouted. The back right Romaine was going the strongest but since I saw a sprout out of the others I had no suspected I was going to run into any problems.
May 12, 2011
But a couple days after that I suspected something was wrong as things had pretty much stalled except the one in the back right. I figured I could not have received two bad Romaine kits. I wanted to add cold water but the plants were not drinking enough to allow me to add it. My only option was to do a partial water exchange and mixing in with cold water from the tap. I did this twice over the next week.
May 17, 2011 (Click this link to see the album and the first harvest)
Well, obviously something was still not quite right (i.e. my water exchange wasn't working). I am sure it didn't help that dumping so much water was also dumping the nutrients that were inserted as well. I wasn't sure that once the plants had stopped growing if they could ever start again. It also didn't help that the one had grown so much it was blocking the light from two of the others. I harvested a couple leaves so the other pods would get light, put it on a sandwich and was amazed at how good the lettuce tasted, almost buttery. After have a taste I decided I couldn't give up. Since the back corner plant was really growing it had started drinking the water down to the point where I didn't have to exchange water... I could simply add ice cold water... So that was the new plan.
May 24, 2011 (Click this link to see the album and the second harvest)
What do you know! Things are starting to move again. The front right pod has moved to the "dead" list as it will not be sprouting but the others are starting to grow again. I do have a problem with the middle back one being blocked from its light but I feel like this is more of a experiment on how to get it right next time... Basically, lesson learned. KEEP YOUR LETTUCE IN A COOL PLACE WITH COOL WATER. Since the lettuce I am getting is so tasty I am going to take what I get for now.