Discussion in 'Lighting' started by jarthel, 15 Nov 2009.
what is it for? I was a looking at a T5 HO setup and it includes 3 whites and 3 blues.
It make the look and feel of the light going into the tank bluish. If it looks too blue for you then add a different color bulb to suit your taste.
no scientific reason like helps in plants photosynthesis at night or anything like that?
If that blue light is 420nm in wavelength, you may try it for red color plants which are current in green.
Well, first of all, photosynthesis cannot occur at night when the lighting intensity is below a certain level. Secondly, after about 8-10 hours of diurnal lighting plants will stop this process so that any additional lighting beyond the normal photoperiod will only encourage algae. Thirdly, plants will use any wavelength within the visible spectrum. It doesn't have to be blue, but blue isn't bad either. The thing is that you probably have enough blue in the white bulbs but really this is no big deal. You're not going to see much of a difference in freshwater plants regardless of what colors you use.
In Marine applications spectral characteristics are related to the performance of specific organisms. So a lot of these tanks have lighting in the blue/indigo/violet regime. In freshwater applications, photosynthetic performance due to spectral differences are minor due to the adaptability of plants. Therefore you would do better to worry about not having too much light intensity for example. That is a much bigger concern, and will cause you a lot more headaches than whether you light is blue or green or red. Worry more about CO2 injection, nutrient dosing and tank maintenance because these will have a much bigger impact than the color of your lights. Find bulbs that appeal to your aesthetic sense and get on with it. Read more about color myths in the thread actinic lighting vs algae growth
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