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Plant ID Help (crypt look-a-like with thick tall stem)

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Plant ID Help (crypt look-a-like with thick tall stem)
Old 01-01-2012, 03:44 PM   #21
 
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Wow, you two are awesome to follow. Would be great to buy you two a few rounds and just absorb the discussion :)

Without having any hard data on the bulbs here is where my minimal knowledge has led me. The Aqueon bulb appears to have a nice 'max intensity' peak in the red for Chlorophyll A but has a lower intensity but broader range for Chlorophyll B. The blue range actually peaks in what I've concluded is the max sensitivity for "low light" leaning towards the purple range just a bit. The green in the 550 range, being the peak for the human eye sensitivity is lower than the red and blue, but still a decent climb just shy of 50. This could explain why the greens in the 10g are brighter. But I would love to see the spectrum on the GE bulbs to further validate.

Also am I correct that with two 10w bulbs over the 10g and only one 17w bulb over the 30g the 10g actually has a higher intensity lighting (at least in the human eye visible range 550ish, which would be green further explaining why that one particular color pops more in that tank) but the red/blue range may not peak as much so it may not be better for plants.

Byron & Quantum, I apologize for tossing in the "amature questions" into your high level discussion, but my mind is eager and this is a ton of knowledge I'm trying to digest here. Am I on the right track (other than my lingo probably being "incorrect"

Also another observation I noticed from the charts Quantum posted is that the Aqueon bulb theoretically has higher output in the photosynthesis ranges than the Hagen Life-glo?

Summarily I'm thinking my 30g tank appears "dimmer" or more drab for lack of better terms, due to the lower intensity in the 550 range vs. the life-glo and/or the common 6500k bulbs regularly used. Another comparison I use is the photos of others tanks, they all appear to be more green than mine. I thought at first it was my plants, but after moving the sword to the 10g under different lighting I know now that is not the case as that thing is vibrant under the CFLs.

I really wish we could get a proper intensity (lumens?) reading on the Aqueon bulb.
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Old 01-01-2012, 04:35 PM   #22
 
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In theory (and it is the one I've based my arguement on), yes the Aqueon would be better for plant growth, but theory and real world don't always coincide, as the experiment cited earlier apparently demonstrates as well as some of the other info Byron has posted.


It is hard to compare your two tanks regarding how the light appears since we're talking two different bulb types, wattages etc. But in a hypothetical situation with every other aspect equal except for bulbs I would contend that the one with the bulb that produces more green light should appear brighter due to the fact that our eyes are more sensitive to the green light. There is also the issue of reflected light, which also would be greater here since the plants reflect the green light energy. All other things would have to be equal though, it wouldn't be a good comparison if one of the bulbs emitted a lot more light than the other.
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Old 01-01-2012, 04:50 PM   #23
 
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Well the two CFL's are putting out 10w each so 20w total, while the 29g is only putting out 17w. But from what I've gathered from your and Byron's post that is hardly an accurate measuring tool due to the multitude of other factors. The reflection would explain the brighter green though. Some other variables would be hood style. The 10g with the screw in hood has a wider "reflector plate" than the 29g, this is very noticable on the surface plants, there is a lot more front and back "shaded" area on the surface of the 29g than the 10g. I assume due to the more narrow reflector above the bulb. I'm also sure the deeper depth of the 29g is another factor to consider as well. Lastly to toss in another variable; the tannins/water color. The 29g has a lot more tannin (very large, fresh Malaysian wood in there). Even with weekly 25% water changes the water comes out very stained while the small wood in the 10g barely leaks any at all, after having the wood in there for a week, water change color was clear. The water color is especially noticable if you put it in a cup (I do this to thaw out the bloodworms and beefheart). Even a scoop from the top of the 29g is very colored. (I personally like it) but would assume this would also play a part (negatively?) in the light penetrating the water.
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Old 01-01-2012, 04:52 PM   #24
 
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Also, I probably should have use the action spectrum rather than the absorption graph. Here's the action spectrum.



It shows the actual rate of photosynthesis relative to light spectrum.
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Old 01-01-2012, 04:55 PM   #25
 
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Quote:
Wow, you two are awesome to follow. Would be great to buy you two a few rounds and just absorb the discussion
I have often wished some of us could "get together" over discussions, it is easier to have a dialogue verbally as things pop into our various heads. Chat may come a bit close, but still not the same when you have to wait between posts for people to type.

Quote:
Without having any hard data on the bulbs here is where my minimal knowledge has led me. The Aqueon bulb appears to have a nice 'max intensity' peak in the red for Chlorophyll A but has a lower intensity but broader range for Chlorophyll B. The blue range actually peaks in what I've concluded is the max sensitivity for "low light" leaning towards the purple range just a bit. The green in the 550 range, being the peak for the human eye sensitivity is lower than the red and blue, but still a decent climb just shy of 50. This could explain why the greens in the 10g are brighter. But I would love to see the spectrum on the GE bulbs to further validate.
The spectrum chart for the Aqueon shows a high peak in the red, but note the thickness of the blue. And as Karen noted in the bit i cited, Kelvin is the measurement of perceived colour, and the same K can come from quite different spectrum tubes. This is one reason I tend to mention specific tubes in posts; I have used them, I know their spectrum graphs, and what they look like. From the spectrum, I would think the Aqueon is going to give a purplish hue, am I correct?

The GE Daylight CFL stats I found indicate 6500K, 82 CRI; Lumens 900 initial, 738 mean; this for the 15w. The 20w is the same except Lumens are 1200 initial, 925 mean. I have these in 10w over my 10g and 20g tanks and the light is very good, plants grow very well, and algae is less in these tanks as any of my 7.

Quote:
Also am I correct that with two 10w bulbs over the 10g and only one 17w bulb over the 30g the 10g actually has a higher intensity lighting (at least in the human eye visible range 550ish, which would be green further explaining why that one particular color pops more in that tank) but the red/blue range may not peak as much so it may not be better for plants.
It would depend upon the makeup of the bulbs. If they are identical, then yes, in this case more watts will mean more intensity. But all else has to be identical. If either was "better" to start with, that could affect intensity either way.

Quote:
Byron & Quantum, I apologize for tossing in the "amature questions" into your high level discussion, but my mind is eager and this is a ton of knowledge I'm trying to digest here. Am I on the right track (other than my lingo probably being "incorrect"
Questions are never a problem for us, any of us; I certainly wouldn't be here if I didn't want to learn and offer advice when I can to others. I love this hobby, but only when one succeeds. Helping others succeed with minimal fuss is my goal.

Quote:
Also another observation I noticed from the charts Quantum posted is that the Aqueon bulb theoretically has higher output in the photosynthesis ranges than the Hagen Life-glo?
Presumably. But the intensity is weak, so this is not an advantage. As Karen noted, without sufficient intensity the spectrum is somewhat irrelevant. And just to add another wrinkle into this. Diana Walstad writes,
I would also argue that green-yellow light is what many submerged aquatic plants encounter in their natural environment. Aquatic light is not like terrestrial light where the blue and red wavelengths predominate. Aquatic light is unique. This is because the water itself absorbs red light, while DOC [dissolved organic carbon] absorbs blue light. What's leftover for plant photosynthesis is mainly green-yellow light. Aquatic plants may have adapted their photosynthetic machinery (over the course of evolution) to use green-yellow light fairly efficiently.
It is important to bear in mind that our aquarium plants are not all true aquatic plants; many--swords, crypts, Anubias, Java Fern to name a few--are amphibious bog plants that spend half the year terrestrially when they flower and have the most growth. The submersed stage is rather like a "rest" for them. Grown permanently submersed as we do in an aquarium, the light needs to provide what they need terrestrially to some extent.

Quote:
Summarily I'm thinking my 30g tank appears "dimmer" or more drab for lack of better terms, due to the lower intensity in the 550 range vs. the life-glo and/or the common 6500k bulbs regularly used. Another comparison I use is the photos of others tanks, they all appear to be more green than mine. I thought at first it was my plants, but after moving the sword to the 10g under different lighting I know now that is not the case as that thing is vibrant under the CFLs.
This is the perception aspect. And remember, that green-yellow is brighter to us. The colour of the light will affect the appearance quite a bit. I prefer a cooler white as opposed to a warmer white; but I also like the yellow-green to be present as this results in a very true colour rendition. As I think Karen noted in that excerpt I cited previously, 5000K to 6500K is closest to natural sunlight, so colours will naturally be "natural" to us. If memory serves me correctly, sunlight is around 5500K, and the 6500K or 6700K (Life-Glo and ZooMed Ultra Sun) add the slight "coolness" to this for a crisper white.
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Old 01-01-2012, 05:33 PM   #26
 
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Quote:
Originally Posted by Byron View Post
The spectrum chart for the Aqueon shows a high peak in the red, but note the thickness of the blue. And as Karen noted in the bit i cited, Kelvin is the measurement of perceived colour, and the same K can come from quite different spectrum tubes. This is one reason I tend to mention specific tubes in posts; I have used them, I know their spectrum graphs, and what they look like. From the spectrum, I would think the Aqueon is going to give a purplish hue, am I correct?
I've seen the purble hue put out by plant bulbs and the Aqueon doesn't resemble that, it may have a slight hue to it but it's hard to tell (I don't notice it). Possibly due to it clashing with the redish/brown tannins in the water? Then again, I just turned and looked at the tank and there is a very very slight purble hue noticable on the surface reflection, far from that put out by the "plant bulbs" though. I did notice the wider blue spread in the spectrum, and from looking at the action spectrum Quantum just posted it appears it actually fits in there relatively well.

Quote:
Originally Posted by Byron View Post
The GE Daylight CFL stats I found indicate 6500K, 82 CRI; Lumens 900 initial, 738 mean; this for the 15w. The 20w is the same except Lumens are 1200 initial, 925 mean. I have these in 10w over my 10g and 20g tanks and the light is very good, plants grow very well, and algae is less in these tanks as any of my 7.
You by chance don't have an image of the spectrum would you?

Quote:
Originally Posted by Byron View Post
Presumably. But the intensity is weak, so this is not an advantage. As Karen noted, without sufficient intensity the spectrum is somewhat irrelevant. And just to add another wrinkle into this. Diana Walstad writes,
I would also argue that green-yellow light is what many submerged aquatic plants encounter in their natural environment. Aquatic light is not like terrestrial light where the blue and red wavelengths predominate. Aquatic light is unique. This is because the water itself absorbs red light, while DOC [dissolved organic carbon] absorbs blue light. What's leftover for plant photosynthesis is mainly green-yellow light. Aquatic plants may have adapted their photosynthetic machinery (over the course of evolution) to use green-yellow light fairly efficiently.
It is important to bear in mind that our aquarium plants are not all true aquatic plants; many--swords, crypts, Anubias, Java Fern to name a few--are amphibious bog plants that spend half the year terrestrially when they flower and have the most growth. The submersed stage is rather like a "rest" for them. Grown permanently submersed as we do in an aquarium, the light needs to provide what they need terrestrially to some extent.
hmm Interesting points there. I used to be a dive instructor (inactive for 6 years now) and this is all rekindling my previous 'obsession' with the physics. Even then though the plant specific physics were very limited in the cirriculum, just enough to explain the basics of how water/depth effects color. A common question was "how come all the coral loses color the deeper we go". Good ol' ROYGBIV. So knowing that red is the first color to get absorbed and penetrates the least into the water, the Aqueon peaking in this area, although along a more narrow spectrum should minimize the already minimal effect of this, after all were only talking about a 15" depth in the 29g. Red usually loses it's color around 20ft (roughly). I used to prick my finger at depth (around 40-50ft) to show the students how blood appears green.

You may find this interesting and inline with what you referenced above (found at The Nature of Light - great read by the way)
Rarely however does just a single frequency (or wavelength) of light strike an object. While it does happen, it is more usual that light of many frequencies or even all frequencies are incident towards the surface of objects. When this occurs, objects have a tendency to selectively absorb, reflect or transmit light of certain frequencies. That is, one object might reflect green light while absorbing all other frequencies of visible light. Another object might selectively transmit blue light while absorbing all other frequencies of visible light. The manner in which visible light interacts with an object is dependent upon the frequency of the light, the nature of the atoms in the object, and often the nature of the electrons in the atoms of the object.
If plants through evolution were absorbing the green light, wouldn't they appear another color, or less green as they would be absorbing that color rather than reflecting it? However, as you mentioned, with swords and crypts for example being amphibious, this is a moot point. Even though, the Aqueon provides a decen spike in this green range.

Also on the topic of red light, you mentioned the rather narrow width of the red spike, in reference to Quantum's action spectrum, red peaking any further in the spectrum would be useless for the plants as they appear to only absorb the "early red".
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Old 01-01-2012, 05:57 PM   #27
 
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Just wanted to mention a word about the wattage. The numbers given for bulbs, as Byron mentioned, is electrical input, this is an important point.

It is also true that light energy output is measured in watts (see my other post), but as far as I know all the watt numbers given are electircal input, though having the output energy I think, would go a long way in clearing some things up.

As far as the red light question. Anything higher than around 700nm wavelength doesn't have enough energy to support photosynthesis. Energy is inversely proportional to wavelength, so the longer the wavelength, the lower the energy.

Last edited by Quantum; 01-01-2012 at 05:57 PM.. Reason: spelling
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Old 01-02-2012, 11:07 AM   #28
 
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Just some final thoughts if anyone is still interested.

First, I believe my point regarding lumens is valid. The difference between radiometry and photometry (luminous power vs radiant power, lumen vs watt, illuminance vs irradiance) means that with lumens, human perception is entered into the equation and human perception and photosynthesis are unrelated. In an earlier post when describing the weighting according to the luminosity function, I incorrectly used joules [energy] where I should have used watts [power], but I was correct in describing the process. For reference: 1 watt of 555 nm light is equal to 680 lumens and 1 watt of 500 nm light is equal to about 200 lumens, and so on. This is the whole idea behind my assertion that lumens can be misleading when talking about photosynthesis. Some light energy counts for more lumens than others, and the light that is 'worth' the most lumens is light that is least useful for photosynthesis. Another way to think about it is to consider UV radiation. It is the same electromagnetic radiation as visible light (just shorter wavelength) and can be measured in watts. But, since humans can't see it, there could be a large amount of UV watts but it would have zero lumens. I will concede, however, that for practical purposes, lumens, lux, etc seems to be a commonly used metric when considering fluorescent tubes. My guess is this due the fact that lumen numbers are all that are usually available, so its a case of making due with what is there, even if it is not ideal. It just seems to me that because of the human-centric nature of luminous power, radiant power would be more appropriate measure regarding photosynthesis. In certain situations this would be less of an issue, such comparing the lumen count of tubes with similar spectral outputs, say for instance similar tubes from different manufacturers. In this case the luminosity function weighting is neutralized so that a lumen count would be a direct comparison of light energy output. But for this discussion we are primarily talking about comparing tubes with different spectral outputs.

Overall, I think the science I've based my argument on is sound. The absorption and action spectra for chlorophyll, the luminosity function graph and how it is related to lumens. All the reasons that of two fluorescent tubes of equal wattage input and equal wattage output*, the one that emits mostly red/blue light (and would likely appear dimmer and have the lower lumen count, for the reasons I've listed) should be better for plant growth than one that emits more greens and yellows (and appears brighter and has higher lumen count). The experts cited apparently recommend the full spectrum tubes, though this doesn't necessarily disprove my case as other factors seem to have played a role, such as cost and aesthetics. Experimental data would provide the answer and I'm curious what this would show. I'm also curious how the cited experiment was conducted. Did they only consider input (electrical energy usage) and spectral graphs as presented by the manufacturer or did they ensure that the tubes emitted the same amount of light energy and did they independently verify the spectral output? These would be two very different experiments.

*I have been assuming that tubes of equal wattage input (electrical usage) will, regardless of spectrum or manufacturer, produce similar, or at least not significantly different, amounts of light energy (watts). It may be that what makes a bulb produce red and blue light also makes it much less efficient at converting electricity to light (the low intensity that Byron has mentioned), though lumen count would only be an indirect (and possibly misleading) measure of this (unless converted to watts).

This is not to say that I will buy the plant tubes, I probably won't. I'll go with the 6500K full spectrum ones.
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Old 01-02-2012, 12:30 PM   #29
 
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I'm still interested, although I think it's down to just you my and Byron now haha.

To hopefully convert your post to my interpretation (in layman's terms):
Where you stated "For reference: 1 watt of 555 nm light is equal to 680 lumens and 1 watt of 500 nm light is equal to about 200 lumens, and so on" and again where you stated "It may be that what makes a bulb produce red and blue light also makes it much less efficient at converting electricity to light (the low intensity that Byron has mentioned)"
This would explain the "dimmer" visible appearance of the Aqueon tube compared to the GE CFL's as they have a higher average spread in the lower spectrum (blue range). Therefore, probably are putting out less intensity "lumens". Than the GE CFL tubes which in all probability have a more balanced spectrum (higher in the mid green/yellow range) to provide better and "brighter" aesthetics for common household/industrial use.

You are right though, it depends on the discussion and application at hand. For the sole intensive purpose of growing plants, theoriticaly the plant bulbs should be better despite the less intensity. However two twists to that are, all the 'non-scientific' results I've read the general consensus is that plants actually grow better in full spectrum 6500k lighting. So maybe aquatic plants are somewhat engineered to better utilize the mid spectrum than we commonly believe or lumens do play a higher role in photosynthesis.

I think we are splitting hairs now, please don't take that. I'm LOVING this discussion, but at the end of the day most aquarists are not just keeping plants, we have fish, and near the top of the list is our visible enjoyment (aesthetics). Which is what most of the referenced studies do incorporate into the equation. So for a balance I'm with you and Byron, my consensus is 6500k lighting is the best all around. I am very interested though in my non-scientific experiement with my two tanks and differing bulbs since I actually kind of prefer the subdued look of the Aqueon tube vs. the GE CFL so as long as plant growth is comparable (they still live and grow even moderatly) I would take that trade over the brighter bulbs that produce higher plant growth.

But the bit about Lumens being relative to the distribution of the spectrum is interesting. Comes back down to the base point of why is the higher lumen 6500k bulb better for plant growth than the lower lumen plant bulb?
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Old 01-02-2012, 01:17 PM   #30
 
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Yes, even at the same output wattage, the red/blue heavy tubes will necessarily look dimmer than green/yellow tubes due to the variable sensitivity of the human eye.

And, if I'm right about the efficiency aspect, this would mean that the plant tubes would also be producing less light overall.

So in the case of the 2 full spectrum 10 watt CFLs vs. one 17 watt plant T8:

- CFLs, I think, are more efficient to begin with
- inefficiency due to spectrum that I've guessed at (and this is just a theory, but it seems to fit)
- difference in percieved brightness of the light produced

This would mean that, at similar electrical usage (20w vs. 17w), the CFLs would be converting a greater percentage of a larger number of electrial watts into light energy at wavelengths that appear brighter. The difference should be quite apparent.

And yes, I think my theory regarding spectrum and plant growth is sound, but there obviously is something else going on. Be it the efficiency angle, aquatic vs. terrestrial envrionment, aquatic plant physiology, or a combination of these and others.

A nice experiment with the data published/peer-reviewed would be interesting and may be out there somewhere

Last edited by Quantum; 01-02-2012 at 01:19 PM.. Reason: formatting and grammar
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