energy saving light bulbs

[TyroneGenade]

Hi all,

Have any of you had much luck growing plants under the energy saving light bulbs? The flourescent replacements of the old trusted incandescent.

I have them over my tanks and see some growth. I'm using the warm whites as I prefer the colour and they seem brighter to my eye.

I will try gather some pictures...

The lemna is triving but some stem plants and indian fern aren't having any of it... Jave moss is, as per usual, A-OK. As are the Anubias.

Regards

[FC]

Those bulbs are similar to PL or T5 ones in term of light reproduction whereby small diameter tubes are used. It provide high intense (brightness per given surface of the tube) and focused light.

Generally, flourescence light output (in lumens) is best at about 4000 Kelvin type colour.
- 2700K is warm white
- 4000K is cool white
- 6500K is day light

[arvin555]

Disclaimer first: I'm new to the forum, but have had some experience with planted tanks from maybe 5 years ago.

As FC mentioned they are similar to PL lamps, which usually has an external ballast, like Flourecent lamps. However there are models that has sockets like incandecent bulbs, these are bulkier as a whole bulb assembly, but work the same way. One disadvantage I guess is that because the ballast is built in, heat wil be rediated from that too, unlike PL types which when we home made one before (still working today) the ballasts were located outside the hood.

I also agree with FC that if possible please use "Daylight" types, those will probably put out the best spectrum for your plants, then again Mosses might not need that much intensity.

Have fun!

TTFN
Arvin

[SQUEAK]

Hi all,

Have any of you had much luck growing plants under the energy saving light bulbs? The flourescent replacements of the old trusted incandescent.

Indeed, I have. I do not like the incandescent too much, as part of the BB radiation, you have a lot of heat generated, and efficiency loss for the visible spectrum. That is, if you look at the spectrum of ID lightbulbs, you will see a heavy weighting towards the low frequency (high wavelength), particularly in the infrared spectrum. Consider though, the fact that these spectrums are only really good when considering a vacuum. For an upcoming project, I'm trying to get some optical cabling to make a more precise measurement of transmission into water. There are some significant differences - especially the absorbing/scattering of red light (another hint of why I don't like ID bulbs for aquatic!). I believe red light has a significantly faster attenuation in water than the higher frequency light (e.g. green, blue, etc), but I am not sure on that off the top of my head.


users.mis.net


Incandescent, gelighting.com

If you observe the spectrum of a fluorescent bulb, you're going to see a better efficiency in terms of what we can measure (this is in part why a fluorescent spectrum will appear the same brightness at less wattage). I haven't done a good comparison of how well the spectrum correlates with a typical plant absorption spectrum, but just eyeballing suggests that fluorescent would be adequate.


Cool White, gelighting.com

I have them over my tanks and see some growth. I'm using the warm whites as I prefer the colour and they seem brighter to my eye.

I will try gather some pictures...

This is probably due to a better matching of the BB radiation reading, and your visual spectrum (assuming the same wattage bulb). The better the correlation, the brighter it will appear. Incidentally, blackbody radiation patterns are only a rough approximation of what you will get out of a fluorescent or a CFL lighting, as we are not dealing with, well, blackbody radiation. It is a system far more suited to ID bulbs.

The lemna is triving but some stem plants and indian fern aren't having any of it... Jave moss is, as per usual, A-OK. As are the Anubias.

Regards

Off the top of my head, I can't think why there would be that difference - I'll let you know if I think of something though.

[TyroneGenade]

Cool colour spectrums. Can you point me to one of a warm white flourescent?

So far, my stem plants are doing well---particularly the Ludwigia arcuata.

Thanks

[SQUEAK]

For some more information on color spectrum, specifically relating to this topic: http://www.thekrib.com/Plants/Tech/light-spectrum.html

I do not necessarily agree with all of their information - as I do think that there is the odd fact skewed (mostly by confusion on efficiency).

Please see:


Warm White, gelighting.com

[TyroneGenade]

Wow, looks just like the cool white spectrum...

[SQUEAK]

I had typed up half an essay in reply.

Unfortunately, when I posted the site timed out, and I accidently closed the window . Thus, life continues down it's rambling pass to annoy me.

The synopsis:

1. People worry too much about kelvin rating. IMO, it is not a good system to use. We use it for comparison against an application where it is appropriate - it works roughly, but not technically accurate. This hobby is unfortunately, largely the blind leading the blind when it comes to anything technical. I have seen some of the most ridiculous statements on aquariacentral and petfish, in particular (can't grow plant under 5500k? Give me a break).

2. Warm and cool white have very closely correlating spectra. There are some minor difference in the spectral power density that are of some note in special applications possibly, but IMO not enough for average aquarium.

I had more thoughts. But this week was just too long for me to be able to think anymore. Sorry, if I think of what I was talking about, I will post again.

[TyroneGenade]

Thanks for all the info Peter. I tried to use the GE site but got hopelessly lost. hats off to you for your thoughtful contributions!

Thanks!

[SQUEAK]

Hi Tyrone,

Please let me know if you're looking for other information on that site, or other information with lighting - I will see what I can dig up.

[whuntley]

Bloviating Mode <ON>

"Cool White" and "Warm White" have some specific meanings, at least in the trade here in the US. The former is rather poor for plant growth, while the latter is quite satisfactory. Their spectra are very, very different!

The human eye has about 1/8 diopter of chromatic aberration in the blue and red ends of the spectrum. Most folks focus best in the green, around 500-520 nm. We also have about 10% the sensitivity in red or blue as we have in green.

"Cool White" fluorescents were developed for office lighting and applications where reading and seeing detail was important. There is a strong peak in the green region, with red and blue suppressed enough that the eye still thinks it is seeing "white" light, but focus is relaxed and easy.

Plant action spectra typically have strong peaks in red and blue, with almost no response in green. In fact, the green hump in "Cool White" spectra corresponds rather well with the dip in the plant spectra. Ever notice how most plants reflect away a lot of the green light? Well, that's because they don't need so much of it.

"Warm White" tubes are trying to simulate the illumination of incandescent lamps. They make red meats look more attractive in the butcher case, and also have enough more red light to be useful to plants. "Chroma50" is a standard lamp developed mostly for the meat case trade.

"Daylight" lamps usually have so much more red and blue in their spectrum that plants love them. Unfortunately, they tend to look quite dim to the human eye.

"Kelvin" numbers are quite useless in evaluating lamps for plant illumination, as are other human-based numbers like Lux and Lumens.

In general, I have found the best plant lamps are those with the lowest lumens/Watt! They don't look so bright, but they have more useful plant spectra.

B. Mode <OFF>

Wright

[SQUEAK]

I am not aware of this large spike in the green spectrum - do you have any power v. frequency plottings of cool white vs warm white? Perhaps mine are incorrect.

I have used 3200k, warm white, cool white all with good results. I run 2 of my tanks on cool white currently, 1 on warm white - no significant differences that I've ever observed.

I'm not aware to their spectra really being significantly different at all. I 'hear' it a lot - but that's another story in itself.

[Happy Camper]

Hi Tyrone

Long time no chat. I have used the energy saver bulbs we get here with success. I had 2 bulbs over a 10gallon tall tank and it grew the plants like gangbusters. I tried the cool white and warm white bulbs and really did'nt notice much difference in terms of plant growth. Perhaps try one of each over your tank?

Regards from your fellow countryman
Cameron

[FC]

One should not conclude the performance of a lamp without considering other parameters like:
1) The plants - slow or fast or easy grower
2) The water parameters - temperature, CO2, etc

General/common flourescent lamp colours are design to suit human's usage in area of:
1) Reading - Cool White or Daylight
2) Decorative - Warm White

For plant, daylight is prefered because it has spectrum that is favourable to plant. Equally important, the colour is right/non-bias to bring out the best of plants' colours.