Interesting Lighting Article for everyone

[revengeishere]

So it seems that in most cases, the spectrum really doesn't matter and that intensity os more important.

http/www.uaf.edu/coop-ext/publications/f.../HGA-00432.html

 

[allnatural]

Oh geez revengeishere, I hate to do this to you, but you are right and you are wrong.

Some clips:

"Critical experiments show that maximum growth of most plants under cool white fluorescent lights will be equivalent to or better than that obtained under the blue-red phosphors...."

and another:

"Blue-red fluorescent tubes may elicit an adequate response from some crops, but cool white light is as, or more efficient for most crops."

The "cool white", "blue-red" are referring to spectrum, not intensity. They are stating that using the cheaper cool white bulbs are just as good IF NOT BETTER than blue-red phosphors. Actually I have read recently that the yellow-green spectrums are good for aquatic plant growth even though many of these lights try to remove these colors, and the article says they are not. Hmmm. Science is not so exact. IHO, a full spectrum bulb is best.

Also, the article is referring to land plants, not aquatic. I would have to do some digging to get some info on light spectrums for freshwater aquatic plants. Water reflects and refracts, so some "colors" may punch through better than others.

But you are right! Intensity is MUCH more important. However consider that if you put a marine bulb which is rich in the blue spectrum over a planted tank with the same wattage, I wonder if the plants would do poorly? You would probably get a "yes" from most aquatic plant hobbyists, although I've never tried this.


--Tim

 

[revengeishere]

I know, I'm just saying that spectrum is just way overrated(well, it is important still...but). I mean, I use combinations myself(cool whites and broad/full spectrums). I'm just saying there are alternatives to those overpriced specialty bulbs and that choosing light bulbs is really simple, and there is no need to be a rocket scientist just to be sucessful in growing a planted tank....

Also, about the blue light, I'm not saying it like that, my intention was more on the cool whites(cheap!). Ive been trying to lower the cost of maintaining/running my aquarium, without comprimising plant growth, and the fish. I don't know even know if blue is really that good(although, I would go with just an all blue spectrum bulb. like you said, its better to have combinations).

 

[allnatural]

Agreed, spectrum is overrated. Your original post said nothing about the cost of lights vs the spectrum. I thought you were talking about spectrum on it's own. Sorry about the confusion.

 

[revengeishere]

No, sorry .It really was my fault, I just realized I didnt really say those stuff...LOL. Again, my apologies.

 

[Lateral Line]

The article mentions the absorbtion curves of Chlorophyll, but does not actually show them which seemed a little odd to me. For those interested, I have posted the curves and a spectrum, (sadly not to the same scale!), here.

Note the lack of absorption between 500nm and 600nm, the green part. Both forms absorb quite an appreciable amount of UltraViolet also.

 

[Dubby]

Here is good article that explains and compares light output for aquatic plant growth.

Comparison of light sources in planted aquaria

 

[Squimps]

I think I posted this link somewhere here before. It shows some nice comparisons as well.

http/www.culbertfamily.com/jenya/aquarium/lights/

 

[spanky_pp_]

I think I posted this link somewhere here before. It shows some nice comparisons as well.

http/www.culbertfamily.com/jenya/aquarium/lights/

love the website. thanks. also love the rosy barb! aww

 

[mrV]

Full spectrum is enough for plants. If you find, from your country, Philips 9-series like "Philips 965", buy those tubes or 8-series which is TLD-serie (tld means more light). They're ok.

Blue and red lights stimulate plants growing in height and width. Intensity (how high those peaks are) it's important too, because water reduces light a lot!

Some finnish hobbiest made a quite good comparison between diff. tubes and added some spectrums too.

 

[odjbo]

Well, I have a 120cm long, 64cm deep tank, and I opted for the new arcadia t5 lighting. i.e.: 4 bulbs @ 54 Watts per tube, making 216 Watts.

I have a Tropical Plant Tank, and this new system is designed for a Marine tank, with 2 X Actinic Lights and 2 X White Light tubes. I had the actinic replaced with the White tubes, as they are so new that is all that is available on the matket at the moment.

Anyway, to cut a long story short, I have been forced to suppliment the lighting with 2 X 30 Watt Flora Glow and 1 X 18 Watt Moonlight, to produce ANY kind of pearling. (CO2 is at 20, or 2 to 3 bubbles per minute)...

My point is, white light alone did not stimulate healthy photosysthesis.

D.

 

[odjbo]

Thanks mrV, just checked out that lighting comparison site...

I have been looking for a spectrum comparison to work out (generally) what light is required in which aquatic zone, i.e: from dense jungle to deep water coral...

Spectrum analysis would be another good link, IF you have such a thing... i.e.: What each part of the spectrum is/does and what it provides with regard to photosysthesis.

Kind Regards,

D.

 

[Lateral Line]

I published a chlorophyll absorbtion spectrum earlier in the thread. You want good phtotsynthesis, you need to tickle those wavelengths.

 

[aquamanis]

This isn,t from any aquarium book or site or anything but I,ve been growing hydropnically now for over 15 years and theres is something I can tell you about light spectrum. Now I dont know the scientific reason for this but this is only my observation and that of my hydroponic friends. When there is a lack of blue spectrum, the spacing between the nodes become futher apart and the plant will not be so bushy and you end up with a long stringy plant. The red part of the spectrum is used by the plant to promote flowering. Without enough red the plant wont have half as many or colourfull flowers and also it helps to create new offshoots. So for full growth from a full bushy plant to having it flower requires a full spectrum. As somebody mentioned you could stuff 1000watts of white light above a tank and it would look almighty bright but would do didly squat for plant growth.

 

[odjbo]

That's what I was thinking Lateral... Thanks for the link...

And thanks to aquamanis for that insight... Now I have the concept, I have to go and discover WHY ! Good fun EH ! (Well it is for me)...



D.