Hi, I have read from previous topic regarding color of light vs wavelength. It is a bit confusing for on my self as I do not have any background on this. Hopefully someone could chime in and educate myself. Here it goes, it has been lingering in my head that the color of light emitted by a bulb (or any other source) corresponds to the wavelength. I am into corals and they need a specific light wavelength/ color (if I may say) which is around 430nm to 500nm to thrive base on my readings on coral propagation. Most light sources (fluorescent, LED) have purplish or bluish shade if we go for that range of wavelength. An example, actinitic light bulbs are on this color and fall within the wavelength range (430 to 485nm). Am I correct to say that my assumption or notion on color vs wavelength is correct? Another thing, I have read that using optical filters (glass or plastic sheets) could limit/filter the light on the discharge side. Say, I buy a PAR 38 LED bulb (daylight) then use an optical filter (plastic sheet or glass) to emit color or wavelength necessary for coral growth (which is stated above). Can I do this? I am trying to make my hobby more economical by enlightening myself (and others) using scientific facts. If the above is doable, this is great news. Please help. Thanks.