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can I cram up my plants like this??

This is a discussion on can I cram up my plants like this?? within the Beginner Planted Aquarium forums, part of the Beginner Freshwater Aquarium category; --> Intensity is a misnomer.. Intensity is not brightness, it's output (in watts). Aqua-glow outputs less lumens, but not less light energy. Lumens are skewed ...

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can I cram up my plants like this??
Old 05-08-2011, 12:40 PM   #11
 
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Intensity is a misnomer..

Intensity is not brightness, it's output (in watts). Aqua-glow outputs less lumens, but not less light energy.

Lumens are skewed by the way our eyes pick up light... Our eyes pick up greens stronger than any other color, so a 20W green bulb will appear much brighter than a 20W blue or red bulb, even if the output is actually the same in Umols (another method of measuring light).

Plant bulbs are great, but do appear dim to us. The plants will do well, but we may not be able to see them. (If you like a purpleish fish tank, it may be perfect for forest fish for the same reason.)

(Sunlight is closer to 5000k, and moonlight is 18000k.)

6500k has been proven to be the best frequency for plant growth in planted tanks though, if you can only use one bulb.
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leogtr (05-08-2011)
Old 05-08-2011, 02:41 PM   #12
 
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It may be time to decipher what we mean by the terms we use and look at this more closely.

Intensity means the strength or brightness of light. High light plants are those requiring more intense light, low light plants require less intense light. Intensity is measured in lumens, which is the output of a light source. A lumen is the unit of luminous energy, historically the light from one candle. So the higher the lumens, the higher the intensity of the light. The intensity of light reaching a surface is measured in units of lux, which is the measure of lumens per square metre.

Watts is the measurement of energy used by a bulb or tube to produce light and heat. As will be obvious later, it has no direct bearing on the brightness or intensity or strength of the emitted light, though when considering bulbs or tubes of the same type then the higher the watts the brighter the light. As an example, a 60w incandescent daylight bulb will produce half the light intensity of a 120w incandescent daylight bulb; but a 60w daylight bulb will not necessarily produce the same intensity of light as a 60w warm white, or cool white. And the intensity of a 60w fluorescent tube will be something else again.

Light used for photosynthesis involves what is called “pigment excitation,” which is a photochemical reaction. Photosynthesis is therefore the photochemical reaction of the chlorophyll molecule. Biologists measure the light intensity that induces photochemical reactions and express it as photon fluence rates; the symbol used is one that I can’t replicate on my keyboard but it means “micromoles per metre squared per second.” Sunlight is approximately 2,000 of these, and normal light intensity for aquatic plants is approximately 120 of these units according to Diana Walstad. [1]

Converting the micromole units [m] to lumens or lux is complicated; Walstad says too much so for her to bother with it. But as she uses the m unit throughout her book, it is for us to work this out to lumens or lux which are the units usually given by bulb and tube manufacturers. According to the Apogee Instruments Inc. online converter [2], sunlight at 2,000 m is equivalent to approximately 108,000 lux. The 120 m for aquatic plants would equate to approximately 6,480 lux of sunlight, and approximately 8,880 lux of cool white fluorescent light. You will see how complicated this actually is by what follows; and I think Ms. Walstad may be right in suggesting we not bother with conversions.

Comparing these figures to the lux of some aquarium fluorescent tubes is revealing. The Life-Glo 2 48-inch 40w tube produces 320 lux. Even two of these over my three largest tanks only equate to 640 lux, yet this is clearly sufficient for some good plant growth. At this point, I will turn to Peter Hiscock.

Bright sunlight produces 70,000 to 80,000 lux, though most of this is lost before the light reaches the plants in nature. Depending upon the plant species, aquarium plants require between 300 and 6,000 lux. [3] The Life-Glo 2 tube as noted above produces 320 lux. By comparison, the Aqua-Glo same size/watts tube produces 130 lux, or about 2.5 times less light intensity. Regardless of the unit we use, the Life-Glo is clearly more than twice the actual light intensity of the Aqua-Glo tube.

[1] Walstad, Ecology of the Planted Aquarium (2003), p. 147
[2] http://www.apogeeinstruments.com/conversions/lux-ppf.html
[3] Hiscock, Encyclopedia of Aquarium Plants (2003), p. 60
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Old 05-08-2011, 08:17 PM   #13
 
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Talking

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Originally Posted by Byron View Post
It may be time to decipher what we mean by the terms we use and look at this more closely.

Intensity means the strength or brightness of light. High light plants are those requiring more intense light, low light plants require less intense light. Intensity is measured in lumens, which is the output of a light source. A lumen is the unit of luminous energy, historically the light from one candle. So the higher the lumens, the higher the intensity of the light. The intensity of light reaching a surface is measured in units of lux, which is the measure of lumens per square metre.

Watts is the measurement of energy used by a bulb or tube to produce light and heat. As will be obvious later, it has no direct bearing on the brightness or intensity or strength of the emitted light, though when considering bulbs or tubes of the same type then the higher the watts the brighter the light. As an example, a 60w incandescent daylight bulb will produce half the light intensity of a 120w incandescent daylight bulb; but a 60w daylight bulb will not necessarily produce the same intensity of light as a 60w warm white, or cool white. And the intensity of a 60w fluorescent tube will be something else again.

Light used for photosynthesis involves what is called “pigment excitation,” which is a photochemical reaction. Photosynthesis is therefore the photochemical reaction of the chlorophyll molecule. Biologists measure the light intensity that induces photochemical reactions and express it as photon fluence rates; the symbol used is one that I can’t replicate on my keyboard but it means “micromoles per metre squared per second.” Sunlight is approximately 2,000 of these, and normal light intensity for aquatic plants is approximately 120 of these units according to Diana Walstad. [1]

Converting the micromole units [m] to lumens or lux is complicated; Walstad says too much so for her to bother with it. But as she uses the m unit throughout her book, it is for us to work this out to lumens or lux which are the units usually given by bulb and tube manufacturers. According to the Apogee Instruments Inc. online converter [2], sunlight at 2,000 m is equivalent to approximately 108,000 lux. The 120 m for aquatic plants would equate to approximately 6,480 lux of sunlight, and approximately 8,880 lux of cool white fluorescent light. You will see how complicated this actually is by what follows; and I think Ms. Walstad may be right in suggesting we not bother with conversions.

Comparing these figures to the lux of some aquarium fluorescent tubes is revealing. The Life-Glo 2 48-inch 40w tube produces 320 lux. Even two of these over my three largest tanks only equate to 640 lux, yet this is clearly sufficient for some good plant growth. At this point, I will turn to Peter Hiscock.

Bright sunlight produces 70,000 to 80,000 lux, though most of this is lost before the light reaches the plants in nature. Depending upon the plant species, aquarium plants require between 300 and 6,000 lux. [3] The Life-Glo 2 tube as noted above produces 320 lux. By comparison, the Aqua-Glo same size/watts tube produces 130 lux, or about 2.5 times less light intensity. Regardless of the unit we use, the Life-Glo is clearly more than twice the actual light intensity of the Aqua-Glo tube.

[1] Walstad, Ecology of the Planted Aquarium (2003), p. 147
[2] http://www.apogeeinstruments.com/conversions/lux-ppf.html
[3] Hiscock, Encyclopedia of Aquarium Plants (2003), p. 60
this makes me want to be a scientist even more. Are you a scientist Byron? Im sure you know what paludariums are have you ever wanted to build one?? I know I want to after I saw some displays in the WORLD WIDE WEB!!!
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Old 05-08-2011, 10:06 PM   #14
 
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Lol, I might make another topic to further discuss light ;) Wow, it's been a while since I had to type a citation.


Thats true, Watts can only be compared when it's the same bulb.
I actually meant watts of output, not watts of input... A microwave is a good example of watts in not equaling watts out. If you read the sticker on a microwave (usually inside the door), it will list output and input separately.. As an example, mine says 5600 Watt at the top, and at the bottom, it says 1200W output.

Lumen is short for luminous flux. The lumen (symbol: lm) is the SI derived unit of luminous flux, a measure of the power of light perceived by the human eye. Luminous flux differs from radiant flux in that luminous flux measurements (such as lumens) are intended to reflect the varying sensitivity of the human eye to different wavelengths of light, while radiant flux measurements (such as watts) indicate the total power of light emitted. 1

Like all photometric units, the lux has a corresponding "radiometric" unit. The difference between any photometric unit and its corresponding radiometric unit is that radiometric units are based on physical power, with all wavelengths being weighted equally, while photometric units take into account the fact that the human eye's visual system is more sensitive to some wavelengths than others, and accordingly every wavelength is given a different weight.
PAR measurements are also used to calculate the euphotic depth in the ocean. PAR is normally quantified as µmol photons/m2/second, which is a measure of the photosynthetic photon flux (area) density, or PPFD. PAR can also be expressed in W/m2. W/m2 measurements are important in energy balance considerations for photosynthetic organisms. Because photosynthesis is a quantum process, PPFD is generally used by plant biologists.

1 Bryant, Robert H. "Lumens, Illuminance, Foot-candles and bright shiny beads…". The LED Light. Lumens, Footcandles, Candlepower, Measuring Light Output.
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Old 05-09-2011, 11:25 AM   #15
 
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Originally Posted by leogtr View Post
this makes me want to be a scientist even more. Are you a scientist Byron? Im sure you know what paludariums are have you ever wanted to build one?? I know I want to after I saw some displays in the WORLD WIDE WEB!!!
No, not a scientist [almost in a way, I loved science in junior high school], but I love doing research which is undoubtedly why I did so well in university. The enjoyment at sifting through books, studies, papers, etc. has not left me lifelong.

Plaudariums is not a subject for this thread, but yes; in the plant profiles I mention suitability for a plaudarium where appropriate. I had a small one for many years, with frogs, newts and fish, water with a land area. Didn't get so involved as to build a rainforest waterfall or anything, just simple. But the newts bred, so they must have liked it.

Byron.
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Old 05-09-2011, 11:45 AM   #16
 
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To the light discussion: so where does this leave us? Perhaps our issue is providing good light for aquarium plants, according to what we expect from them. And I think we can use all this data to work towards that goal.

The initial issue to which I was responding concerned the intensity of so-called plant tubes like Aqua-Glo and Flora-Gro compared to tri-phosphor full spectrum tubes, and the former produce half the light intensity of the latter, whether one is a person or a plant. The fact that the light colour (spectrum) emitted by the former is aimed at providing the essential red and blue means they will undoubtedly work. But probably not as well as the full spectrum. And my observations using both over a period of years seems to bear this out. It makes more sense to me to be using 40 watts of electricity to provide more light rather than less light.

Kasselmann in her book Aquarium Plants writes that in the final analysis it is best to observe the response of the plants, and adjust the light accordingly. Plants will react to changes in the available light. She notes that they do this in nature, and have had to evolve accordingly or face extinction.

Byron.
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Old 05-09-2011, 12:19 PM   #17
 
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I hope everyone knows I'm not being argumentative.. Just having a conversation.

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To the light discussion: so where does this leave us? Perhaps our issue is providing good light for aquarium plants, according to what we expect from them. And I think we can use all this data to work towards that goal.
Well said.
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The initial issue to which I was responding concerned the intensity of so-called plant tubes like Aqua-Glo and Flora-Gro compared to tri-phosphor full spectrum tubes, and the former produce half the light intensity of the latter, whether one is a person or a plant.
Thats true, I was just caught up because you were referring to lumens and lux... Both are skewed towards the way the human eye interprets light.

.
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Originally Posted by Byron View Post
The fact that the light colour (spectrum) emitted by the former is aimed at providing the essential red and blue means they will undoubtedly work. But probably not as well as the full spectrum. And my observations using both over a period of years seems to bear this out. It makes more sense to me to be using 40 watts of electricity to provide more light rather than less light.
Agree wholeheartedly, thats why no one uses 7000k incandescents or halogen lights.
Quote:
Originally Posted by Byron View Post
Kasselmann in her book Aquarium Plants writes that in the final analysis it is best to observe the response of the plants, and adjust the light accordingly. Plants will react to changes in the available light. She notes that they do this in nature, and have had to evolve accordingly or face extinction.

Byron.
Our plants will tell us what they want and need. Have you always grown 'forest' plants?
When light trickles through trees, it's likely that a good percentage would be reflected from leaves..
Perhaps it would be an interesting experiment to test whether 'forest' plants do better under tri-phosphor and 'full sun' aquatic plants don't need the green hardly at all?

There's still quite a bit of research to be done on PAR...
Leogtr, Are you up for it?
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Old 05-09-2011, 12:26 PM   #18
 
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Quote:
Our plants will tell us what they want and need. Have you always grown 'forest' plants?
When light trickles through trees, it's likely that a good percentage would be reflected from leaves..
Perhaps it would be an interesting experiment to test whether 'forest' plants do better under tri-phosphor and 'full sun' aquatic plants don't need the green hardly at all?
I have to run out the door to go somewhere with my neighbout, but want to return to this later. B.
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Old 05-09-2011, 04:30 PM   #19
 
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Our plants will tell us what they want and need. Have you always grown 'forest' plants?
Generally, yes. I tend to avoid stem plants which generally need more light than I am willing to provide. Floaters of course are up close to the light, so rarely an issue light-wise. Swords, crypts, Anubias, Java Fern, and many others are amphibious plants, strictly speaking not fully aquatic, so light is a different matter.

Quote:
When light trickles through trees, it's likely that a good percentage would be reflected from leaves..
True. As Kasselmann mentions in her book, most "aquarium" plants are not bright-light plants naturally. She also has numerous statistics for specific rivers and streams in SA and SE Asia from studies she carried out as well as other botanists; light, water parameters [very revealing] and plant species data. I've scanned Diagram 1, a schematic representation of the distribution of plant populations in differing living environments in the Rio Guapore (excluding the marsh zone). This is one of the most "planted" watercourses in Amazonia [most lack aquatic plants in the actual streambeds] as our friend Heiko Bleher has well documented. This particular section receives direct sunlight, evidenced by the proliferation of floating plants in this habitat. This can be seen in the photo [from Dr. Kasselmann's book].

Quote:
Perhaps it would be an interesting experiment to test whether 'forest' plants do better under tri-phosphor and 'full sun' aquatic plants don't need the green hardly at all?
As I understand it, all plants need red mainly, then blue in order for photosynthesis to occur. Other wavelengths are used much less, to varying degrees depending upon species. Our old friend the algae can use any light which is why it is so important to provide higher plants with the essential light to enable them to out-compete algae. Interestingly though, Kasselmann [who is a botanist] writes [p. 45], "The latter [plants] require the entire light spectrum for the purposes of photosynthesis, preferably the red (around 700 nm) and, to a lesser extent, the blue (around 450 nm) spectrum range."

The colour of plant leaves is of course due to the reflected light spectrum. Green leaf plants reflect green light and thus appear green to us. Red leaf plants reflect red, and thus these species require more light because they are deliberately giving up some of what they most need to photosynthesize.


Byron.
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File Type: jpg Rio Guapore (Kassselmann).jpg (49.1 KB, 32 views)
File Type: jpg Rio Guapore (Brazil).jpg (59.7 KB, 32 views)
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Old 05-09-2011, 05:49 PM   #20
 
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Just thought I'd add a couple more photos of the plants on the Rio Guapore. B.
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File Type: jpg Eichhornia diversifolia, R Guapore.jpg (85.6 KB, 29 views)
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