Carlos,
so you don't think it has anything to do with the bulb? If I ran this tank with just 6500K bulbs I could achieve the same redness? I understand what you mean with the red tint, but I'm talking about the actual plants color. So the color of the plant is solely a function of the lights intensity and low nitrate, and has nothing to do with the spectrum of the light that reaches the plant. I thought the color of the plant reacted to different peaks in the light wavelength, and that these bulbs were so successful because they peaked high in the red wavelength.