Light spectrum for Aquatic plants

[Shadow]

I read this interesting article from ADA web site "The Light I Encountered Under Water" Below are some of thing that I found interesting. You can read the full story from the link below.

http://www.adana.co.jp/aj_web/na/sto...ind/index.html

also here

http://www.adana.co.jp/aj_web/na/notes/002/index.html


Aqua Journal: Does that mean that light in the red spectrum boosts photosynthesis in aquatic plants?
Amano: Yes. In essence, such lamps were developed because one of the wavelengths used in photosynthesis was in the red range. However, it was still a land-based idea.


Aqua Journal: Is the condition of light different between land and under water?
Amano: Well, when you are on land, you feel like you are in the same level of brightness all the time during the day, don’t you? But it’s completely different under water.


Aqua Journal: So, what did you come up with in the ocean in Sado?
Amano: I was diving in the ocean to take an underwater picture that day. I was taking pictures of baby striped beakfish (Oplegnathus fasciatus) in a field of sea grass, Zostera marina, at a depth of about three meters. When I ran out of film, I happened to look at my arm. My red jacket looked black. What should have been red appeared black.



Aqua Journal: The new lamp development must have started from then on.
Amano: Yes. After that, I visited Sado many times and collected a variety of information. For example, the period you feel bright is very short from 11:00 AM until 2:00 PM. Between 11:00 to 14:00 the sunlight comes relatively straight into water. In the period before or after that, the entry angle of the sunlight is small, and the light reflects off the surface and does not come into water. It’s still bright above, but it is already getting dark below. I also studied about color temperatures of light in detail.


Aqua Journal: Ah, that must be the reason why the color temperature of NA Lamp is 8000 K..
Amano: Right. The 7,800 to 8000 K color temperature range seems to be the most suitable for aquatic plants not only for the growth of aquatic plants but also for color rendering as well.


Aqua Journal: So the color temperatures and the blue light were the key elements for the development of the NA Lamp?.
Amano: Yes. This does not mean that red light is not necessary. Don’t take this wrong. It’s not difficult to change the color temperature of a lamp.
For example raising the color temperature to 9,000 K or 10,000 K is simple. However, the light becomes bluish as the color temperature increases, and it starts to deviate from the original natural color. What matters is the color balance. It’s best that colors appear natural, isn’t it? When you look at nature, like in a river, the light is even more limited. For example, light reaches below the surface for only one hour in a day. Aquatic plants photosynthesize as if they were eagerly waiting for the time.

[d2sign]

Vol.002 is out, thanks for sharing

[Shadow]

After 3 weeks toying with the idea of 2 hours PL follow by 4 hours MH and 2 hours PL, it does not seems to be working. Previously I have 6 hours of MH. After 3 weeks, my rotala start shedding some leaves, especially those bottom part. My E.tenellus which previously reddish color turn back to green. I guess following nature not always good idea can't duplicate sun intensity anyway

[Shadow]

I still doubth LED light can penetrade 1.5ft or 2ft water depth. Lets just wait and see.