# 400-450nm lighting for plants?



## Mark Brown (Jan 21, 2017)

So I have been scouring the Internet for a while now on this topic and I think I have a good idea on it however, I find the more I think I know the closer to wrong I usually am. That being said I'm wondering what kind of success/failure you might all have run into adding this spectrum into a planted fresh water tank?

Thanks


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## CRS Fan (Apr 21, 2010)

Hello Mark.

It is not a useful light range for freshwater plants. I'm thinking the only plant that could use it would be azolla (because of the Cyanobacteria in their tissues).

Best regards,

Stuart


Sent from my iPhone using Tapatalk


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## Mark Brown (Jan 21, 2017)

see that is where I would be confused. there is so very much information on the interwebs about the photosynthesis of plants and from what I can see clorophyl a and b both have the greatest absorbtion rates around 400-500 nm yet it would look to me like it isn't a common practice and for the life of me I cannot figure as to why.


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## Mark Brown (Jan 21, 2017)

I would also like to add that I don't want to come off as argumentative. My idea in asking for advice is definitely not to dismiss people's opinions until I get around to the one I have. I am just really really confused about it all. Is there something in aquatic plants that changes the dynamics or is it just a tried and failed method that people have experienced??


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## dino (Aug 29, 2011)

I don't grow plants except in my refugium but I always thought reds and blues are the most effective for plant growth and that's 400-450 and 600 but im no expert. I use blue and red in my fuge though


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## Tropica North America (Jun 19, 2016)

Mark Brown said:


> I would also like to add that I don't want to come off as argumentative. My idea in asking for advice is definitely not to dismiss people's opinions until I get around to the one I have. I am just really really confused about it all. Is there something in aquatic plants that changes the dynamics or is it just a tried and failed method that people have experienced??


This notion is being tried with commercial nurseries today (not aquatic plant nurseries). In the spectral division of light, plants use mainly the blue (about 400-430nm) and red (about 650-675 nm) wavelengths for photosynthesis. All others in the visible spectrum are not a factor in the process. Plants appear green in colour because they simply reflect this wavelength.

Generally speaking, most aquarists have not had the ability to tinker with the wavelengths they can supply to their aquarium until recently with the advance of LED's. One thing that you will have to be aware of are what is the limiting factor in the photosynthetic process. In providing more light it must be balanced with more nutrients and CO2, otherwise you won't see any improvement in growth. Lights that replicate natural daylight (5500k - 6500k) will do the trick, unless you are simply wanting to play. The other item that may be a factor would be the overall look of your tank while running additional blue wavelength lights. The tank will look cold and may not be pleasing to the eye. But, that is my own $0.02.


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## Mark Brown (Jan 21, 2017)

well I appreciate all the feeback from everyone. I think since no one has come back with "eeeeeegads heavens no!!" that I'm just gonna give it a lark and see what happens. I'm all for being a guinea pig. I'll let everyone know how it works out in a month or so. Just looking for ways to push the envelope on plant development. Still open to ideas though...

thanks!


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