I'm curious to hear more cases of blue lights and aquatic plant growth. In the reefing world, the general feel on the blue light was it didn't really provide anything useful to the coral, and I'm talking the actinic blue bulbs, not 20k which has the reds, yellows, greens ect. It was used to enhance colors and provide moon lighting in some cases. In theory blue light should be great for photosynthesis so I don't see why not. I could see throwing some blue LED's on a tank if for nothing else to pop the colors.