New Chihiros RGB Vivid - looks VERY promising

jaypeecee

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Hi @rebel
Has anyone ever done a spectral analysis of their lights? Is there a machine which can analyse the spectra?
Yes, I've done many spectrum measurements. I use a very low-cost piece of kit called the i-Phos. Please see the following thread:

https://www.ukaps.org/forum/threads/i-phos-budget-spectrometer.61076/

The i-Phos can be calibrated using a CFL. But I used an array of narrow-band LEDs at 395, 430, 470, 568, 625, 645 and 700 nm to calibrate my setup.

JPC
 

Wookii

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Hi @rebel


Yes, of course, aesthetics is important. But, my hunch is that aquarium light manufacturers are homing in on aesthetics at the expense of optimum plant growth. And there is the important matter of minimizing algae and cyano growth.

JPC
I think the myth regarding specific aquarium lights being optimised for plant growth has been debunct a long time ago. Long and short of it is that plants will grow under pretty much any light without issue providing there is enough output in the red and blue spectrum (all other factors being equal). This is evidenced quite simply by the success of many many planted tanks under a vast variety of lights from so called dedicated plant lights all the way to desk lamps and flood lights, including RGB based lights. @ceg4048 can probably provide you with a more technical response, here is one of his prior posts on the subject:

Unfortunately this is another false assumption made by almost everyone, and that is exactly why the comment challenges everything you've read on the subject. What you have read was not written by folks who investigated the specific function of plant pigments. They were told what to think and what to write, so they thought it and then wrote it.

The light harvesting mechanism of plants, algae and some bacteria, such as BGA consists of a central Chlorophyll complex. The complex, has, among many other components, a series of auxiliary pigments which respond to wavelengths of light other than blue and red. The energy captured by these pigments are then passed on to the Chlorophyll and therefore act as a spectral extension of the main Chlorophyll response curve. The leaf analyzes the spectral distribution and fabricates a variety of pigments to perform tasks, such as to reflect wavelengths that have too much energy, to absorb wavelengths that are not primary wavelengths and some pigments are even capable of changing the incident light to another color and reflecting it on to pigments that can then absorb the new color and pass it's energy on to the Chlorophyll.

It's a very sophisticated system and it doesn't need your help. Whatever spectral distribution you provide, the plant will determine how to best use that energy. In this hobby, it actually the opposite of what folks think. There is actually far too much light, that more often than not overwhelms the plants ability to quench the excessive energy.

So there is no demonstration that plants "...absorb light mostly in the blue and red..." It's simply that the Chlorophyll pigment itself has a higher response to blue and red but it depends on the other pigments to absorb the remaining wavelengths and to process those wavelengths. On the contrary, it is specifically because the Chlorophyll pigment has such a high response to blue and red that is is easily overwhelmed by blue and red. So if anything, what the photosynthetic spectrum shows is that you should be using LESS amounts of blue and red to reduce photo-inhibition. This fact has been completely misinterpreted for far too long.

Spectrum loving Klingons are a plague, a pestilence of misinformation on this planet.
We are the cure.....

Cheers,
There are many users with RGB lights now, and I think we would know if it couldn't grow plants, or induced BGA. I've had one on my tank for several months, plants grow very well and I've never had BGA - but then I try and ensure very high DO levels, which I think is a more important factor at preventing BGA.
 

jaypeecee

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Hi @Wookii

I am fully aware of what Clive has had to say on this subject. Suffice it to say that some very-highly esteemed photobiologists seem to be sending out different messages. I have provided the following link several times on UKAPS but here it is again:



And Clive does not touch on the potential for algae and cyano growth. The fact is that light in the band from 400nm - 500nm is able to reduce ferric iron to ferrous iron and this has the potential to promote algae and/or cyanobacteria. The scientific research is readily available for anyone who is sufficiently interested in reading it. Indeed, Diana Walstad discusses photoreduction of iron on pages 167 - 169 of her book*. This is not to say that light in the band from 400nm - 500nm is to be eliminated. Categorically, not. It simply needs to be adjusted in intensity.

* Ecology of the Planted Aquarium.

JPC
 

jaypeecee

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Hi @Wookii
There are many users with RGB lights now...
I just want to understand exactly what you mean by 'RGB lights'. All (white) lighting, LED or otherwise, contains light in the red, green and blue parts of the PAR/visible spectrum. That could be produced by a blue LED with suitable phosphor giving light across the PAR/visible bandwidth. Or, it can be produced by a combined RGB 'chip'. Or, discrete red, green and blue chips. The single RGB 'chip' are geared around general lighting products such as home lighting.

To which of the above are you referring? Or, perhaps, I've overlooked one?

JPC
 

Wookii

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Hi @Wookii


I just want to understand exactly what you mean by 'RGB lights'. All (white) lighting, LED or otherwise, contains light in the red, green and blue parts of the PAR/visible spectrum. That could be produced by a blue LED with suitable phosphor giving light across the PAR/visible bandwidth. Or, it can be produced by a combined RGB 'chip'. Or, discrete red, green and blue chips. The single RGB 'chip' are geared around general lighting products such as home lighting.

To which of the above are you referring? Or, perhaps, I've overlooked one?

JPC
I would have though it would be obvious that we were talking about combined RGB chips with individually addressable channels given you are talking about them in reference to the Vivid II in the thread discussing that product.
 

Wookii

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Hi @Wookii

I am fully aware of what Clive has had to say on this subject. Suffice it to say that some very-highly esteemed photobiologists seem to be sending out different messages. I have provided the following link several times on UKAPS but here it is again:



And Clive does not touch on the potential for algae and cyano growth. The fact is that light in the band from 400nm - 500nm is able to reduce ferric iron to ferrous iron and this has the potential to promote algae and/or cyanobacteria. The scientific research is readily available for anyone who is sufficiently interested in reading it. Indeed, Diana Walstad discusses photoreduction of iron on pages 167 - 169 of her book*. This is not to say that light in the band from 400nm - 500nm is to be eliminated. Categorically, not. It simply needs to be adjusted in intensity.

* Ecology of the Planted Aquarium.

JPC
Whilst interesting, I’m not entirely sure of the relevance of the point in ferric iron production since all standard aquarium lights contain output in that bandwidth, otherwise there wouldn’t be any blue in the light source.

Anyway, we were talking specifically about your thoughts that RGB lights (those with individually addressable channels) would not provide the right bandwidth of red light for optimised growth, and would induce BGA. Whilst scientific links on the topics are always interesting, practical application really has to take precedence.

As I say, these types of LED’s are now in fairly wide use. There are many examples of plants lit by ADA Solar RGB lights (which also appear to have a red Centre frequency at 630nm - they likely use the same LEDs), and various Chihiros RGB lights which all grow plants without issue.
 
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oreo57

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:p
Hi @rebel


Yes, of course, aesthetics is important. But, my hunch is that aquarium light manufacturers are homing in on aesthetics at the expense of optimum plant growth. And there is the important matter of minimizing algae and cyano growth.

JPC
Light spectrum has little to do w/ green algae.
 

Tim Harrison

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I think spectrum matters for various reasons, but I also think that Clive is right in that if other factors are well balanced it shouldn't be of paramount importance. Further, most of the bulbs we use as aquatic plant growers are full spectrum anyway so most plants, if not all, will get what they need in terms of light wavelength to grow healthily.

On the question of adjustable lights...I think different wave lengths can induce different plant morphologies, for example; it is possible to grow plants with marine lights that are heavy in the blue end because plants have accessory pigments that can utilise this light. But not many folk would want to adjust them to the extreme of either blue or red since the result will be ugly buggly ;)
 

Wookii

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Hi @Wookii


I shouldn't really need to say this but, if it had been obvious to me, I wouldn't have asked the question.

JPC
Lol fair enough. So we are in a thread discussing a specific RGB light, and you’ve commented on the same RGB light, and posted specific points regarding the spectrum of that same RGB light, so let’s assume going forward that when we say ‘RGB’ in this thread, we are referring to that same RGB diode used in that same light. ;)
 

Wookii

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Hi @rebel


Yes, I've done many spectrum measurements. I use a very low-cost piece of kit called the i-Phos. Please see the following thread:

https://www.ukaps.org/forum/threads/i-phos-budget-spectrometer.61076/

The i-Phos can be calibrated using a CFL. But I used an array of narrow-band LEDs at 395, 430, 470, 568, 625, 645 and 700 nm to calibrate my setup.

JPC
This is interesting - I was wondering how I could go about measuring the true output spectrum of some lights.

I have a fairly hefty colourmeter (I calibrate projectors as a second part time hobby/job) - I envisaged reflecting an aquarium light on a neutral projector screen and measuring the reflected light with the colour meter.

How do you go about measuring the lights with the I-Phos to ensure a broad colour mix?
 
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jaypeecee

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Hi @Tim Harrison
Further, most of the bulbs we use as aquatic plant growers are full spectrum anyway so most plants, if not all, will get what they need in terms of light wavelength to grow healthily.
The term 'full spectrum' simply means that some light is emitted from a bulb at each and every wavelength from 400nm to 700nm. Chlorophyll a is the main absorber of light by plants. And chlorophyll a absorbs light in the band 400nm to 450nm, reaching a peak response at 430nm. All this is is in the violet to blue part of the spectrum. Chlorophyll a also absorbs red light from 640nm to 700nm, with a peak response at 660nm. Now, if a so-called full-spectrum light produces minimal output at the chlorophyll a wavelengths, it's not going to be much use to our plants. But, it can still be called 'full spectrum'.

My concern lies mainly with the red part of the spectrum. If the red light output from aquarium lighting peaks at 630nm, that's not much use to the plant. It may not be the perfect analogy but I like to compare this with tuning in a radio station. A radio set on 90MHz will pick up Radio 3 - but turn the dial to 89MHz and it won't!

JPC
 

Wookii

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Hi @Tim Harrison


The term 'full spectrum' simply means that some light is emitted from a bulb at each and every wavelength from 400nm to 700nm. Chlorophyll a is the main absorber of light by plants. And chlorophyll a absorbs light in the band 400nm to 450nm, reaching a peak response at 430nm. All this is is in the violet to blue part of the spectrum. Chlorophyll a also absorbs red light from 640nm to 700nm, with a peak response at 660nm. Now, if a so-called full-spectrum light produces minimal output at the chlorophyll a wavelengths, it's not going to be much use to our plants. But, it can still be called 'full spectrum'.

My concern lies mainly with the red part of the spectrum. If the red light output from aquarium lighting peaks at 630nm, that's not much use to the plant. It may not be the perfect analogy but I like to compare this with tuning in a radio station. A radio set on 90MHz will pick up Radio 3 - but turn the dial to 89MHz and it won't!

JPC
How would a lack of availability of the appropriate light at the red end of the spectrum manifest itself in a growing plant?
 

jaypeecee

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Hi @Wookii
How do you go about measuring the lights with the I-Phos to ensure a broad colour mix?
In my case, trial and error - at the moment. But, it's working for me. I simply set up the i-Phos with the light inlet slit in the horizontal position. As my current lighting fixture is mounted in a hood, I lift the hood so that the i-Phos is pointing directly at it. The i-Phos is mounted on a camera tripod about 2m from the lighting. That does the trick very nicely.

JPC
 

Tim Harrison

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How would a lack of availability of the appropriate light at the red end of the spectrum manifest itself in a growing plant?
Take a look a this paper http://www.apms.org/japm/vol15/v15p29.pdf
Hi @Tim Harrison


The term 'full spectrum' simply means that some light is emitted from a bulb at each and every wavelength from 400nm to 700nm. Chlorophyll a is the main absorber of light by plants. And chlorophyll a absorbs light in the band 400nm to 450nm, reaching a peak response at 430nm. All this is is in the violet to blue part of the spectrum. Chlorophyll a also absorbs red light from 640nm to 700nm, with a peak response at 660nm. Now, if a so-called full-spectrum light produces minimal output at the chlorophyll a wavelengths, it's not going to be much use to our plants. But, it can still be called 'full spectrum'.

My concern lies mainly with the red part of the spectrum. If the red light output from aquarium lighting peaks at 630nm, that's not much use to the plant. It may not be the perfect analogy but I like to compare this with tuning in a radio station. A radio set on 90MHz will pick up Radio 3 - but turn the dial to 89MHz and it won't!

JPC
I think it can get a bit confusing and I'm certainly not great on the physics of it. But I think in order to get the white light we find so attractive the mix of wavelengths will be of more than adequate quantity for plant growth; remember the prism experiment at school? And don't forget plants have accessory pigments too.
 

jaypeecee

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Hi @Wookii
How would a lack of availability of the appropriate light at the red end of the spectrum manifest itself in a growing plant?
I am a physicist, not a plant biologist. In the first instance, this is where I would turn to Dr Bruce Bugbee's videos and the many resources I have accumulated. I think you'll find that Dr Bruce Bugbee covers this in the video to which I linked above.

JPC
 

jaypeecee

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Hi @Tim Harrison
...I think in order to get the white light we find so attractive the mix of wavelengths will be of more than adequate quantity for plant growth
Because the response of the human eye to the white light spectrum is so different from that of plants, it doesn't help. Our eyes are most sensitive to green/yellow light (around 565nm). Plants' 'eyes' are most sensitive to 420/430nm (violet/blue) and 660nm (red).

JPC
 

oreo57

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Hi @oreo57,

Because?

JPC
Sorry, sometimes I get a bit cryptic to encourage research.
Anyways let's start at the spore level where it all begins
Spores can only eat ammonium.
No free ammonium no algae.
Sources include leaky plant tissue,bacteria decomposition ect

Green algae has basically the same photosynthetic system as higher plants so why would you think spectrum matters?
 

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