So, here is an odd question for anyone.. does anyone know of a place that sells thin plastic sheets that has actual spectral output readings for the plastic? I highly doubt it, but maybe some type of Greenhouse material exists for the same type of thinking. The idea here is to cover the Solar Tubes with a blue film to reduce the PAR of them, and hopefully try and filter out some of the bad lighting while letting the good lighting through still. I know it is a long shot finding something like that... but maybe someone knows. If not, after some LED experimenting of my own, I am going to start experimenting with different plastic films I can find locally and use my par meter and spectrometer to see how each one works. Guillo and I never imagined Solar tubes would work so well.. so now we are looking for ways to actually "refine" them since we know they are far exceeding natural sunlight output. If we could cut the PAR in 1/2 on each of them, but still allow the blue light through, that would be ideal.