4 days later. They are growing so fast that I keep having to move my lights up! The middle one looks a little lighter in color. I have been giving the closest one Calmag water by hand. Within a couple days it has outgrown the other and looks better color wise. So I have been doing the same thing with 2 other plants and they look great too. So I think Biotabs with Coco and cob lights you should probably use Calmag in your water, even tho it says you don't need to. I am experimenting with the Biotabs, so far I am getting the seedlings off to a better start each time. I have many hooked up to the AutoPots being fed RO water only, as directed. But having cobs I know a Calmag def is almost always an issue, unless treated. So I have been hand watering the bottom of the AutoPots of 3 plants with Calmag water. All 3 are a better shade of green and def is not progressing. I am sure I will be adding Calmag to my reservoir in the future...I have a bunch of Sour Cracks that need to come out in 10 days or so. By then I will know how well the Calmag water is working, and most likely will be used on every plant moving forward via the AutoPots reservoir.