# actinic lighting vs algae growth



## aaronnorth (9 Sep 2009)

Is it fact or myth that actinic lighting promotes algae growth?

I know plants can use blue wavelengths, but from what i have read "they can only use so much of the light, because they also need red wavelengths to grow/ photosynthesise efficiently, so this gives algae the edge"

from that, it seems algae is not caused by actinic as a direct result, but rather indirectly due to poor plant health.


Thanks, Aaron


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## Joecoral (9 Sep 2009)

I've always been told actinic promote algae.
This sounds like a job for clive!


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## aaronnorth (9 Sep 2009)

Joecoral said:
			
		

> I've always been told actinic promote algae.
> This sounds like a job for clive!



same, i am not sure if it is one of those things that just gets spread around and then becomes stuck like nutrients cause algae, i havent found a definitive answer on here or the barr report which is the first 2 places i look lol.


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## GreenNeedle (9 Sep 2009)

I think you answered your own question there Aaron 

This is also why the spectrum arguments often fall down when put to the test.  A 'full spectrum' light is all that is needed really. Pink (4000K) or Daylight (5500K+) will all have enough of each in them and therefore we see that plants do not need pink lights to grow properly no matter how many people seem to think they do .  I am using solely 5500K and have no problems. 

The actinic doesn't supply enough of all the spectrum and therefore the plants suffer then the algae take advantage.

I assume it doesn't happen in marine tanks due to the water parameters.

AC


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## ceg4048 (10 Sep 2009)

aaronnorth said:
			
		

> Is it fact or myth that actinic lighting promotes algae growth?
> 
> I know plants can use blue wavelengths, but from what i have read "they can only use so much of the light, because they also need red wavelengths to grow/ photosynthesise efficiently, so this gives algae the edge"
> 
> ...


Hey Aaron, this is patently false and is yet another illusion of The Matrix.    This is so absurd that it actually has great entertainment value. Why? Because blue is the fundamental response wavelength of chlorophyll. I showed this link in another post; Absorption Spectra of Chlorophyll You can see clearly that chlorophyll-a has it's maximum response at 430nm while chlorophyll-b has it's response peak at 453nm. The graph also shows a secondary response peak at 662nm and 642nm respectively. These secondary peak frequencies are in the far red region, so clearly, chlorophyll molecules are optimized around blue+red. Now compare the relative absorption of the two peaks for each type. In the case of chlorophyll-a the absorption of blue is about 20% higher than it's absorption of red. Chlorophyll-b has a 200% higher blue absorption than red absorption. Can you understand what that graph is showing?

The so-called "Actinic 03" bulbs typically have spectral curves with energy peaks at or around wavelengths of 420-460nm. So this plays right into the hands of both chlorophyll types. Of course, the actinic bulbs probably have very little energy in the far red, and they may also emit in the UV region. If that is so, then you ought to be a heck of a lot more worried about what those bulbs are doing to YOU, forget about the plants.   

The hysteria about actinic lighting evidently stems from the basic theory that cyanobacteria and subsequently true algae were the first to develop and use chlorophyll in the ocean, which of course is blue. So everyone panics because they simple-mindedly assume it follows that blue light fosters the development of algae. What they forgot though is that higher plants, descendants of algae, have the same chlorophyll that algae have, so whatever light attracts algae also attracts plants, and whatever light attracts plants also attracts algae. I mean...this should be obvious by now.

There is a good reason why the chlorophyll molecules each have absorption peaks so far apart. That reason is simple; the photoperiod of the Earth is not necessarily homogeneous. In the morning and late afternoon there is quite a bit of red. At or near midday, blue dominates. So it's perfectly logical for the plants to be able to optimize photosynthesis regardless of the time of day. Since there is more blue than red during the photoperiod it also makes sense to optimize the response around blue. The impact of blue and red is not so much growth differences (the photosynthetic rates may not be that far apart), but that appearance of certain colours in the diurnal cycle activates certain behaviour. For example, blue light in some species stimulates the stomata to open wider allowing better CO2 uptake. In some species blue light signals the plant to allocate it's carbon fixation to the fabrication of amino acids and proteins, while red light stimulates the allocation of the carbon to the production of sugars, such as glucose.

As we've noted many times, the plants will adapt to the lighting conditions, so that if you feed the tank only actinic, they will make an adjustment. If you pump too much actinic energy then of course you'll get algae, but how is that different from any other kind of light? 

Cheers,


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## baron von bubba (10 Sep 2009)

so would it be correct to assume that changing the tubes to a different spectrum in an established aquarium "could" cause algae problems?
if as you state the plants adjust to what ever light is offered them, then it stands to reason that a change of lighting would cause a further adjustment in the plants which may "stall" or slow growth.


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## Dan Crawford (10 Sep 2009)

When i got my new halide and T5 unit, it was supplied with marine tubes and man they were blue! I used them anyway for two months to no ill affect, growth was just the same but it didn't "look" as nice.


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## ceg4048 (10 Sep 2009)

baron von bubba said:
			
		

> so would it be correct to assume that changing the tubes to a different spectrum in an established aquarium "could" cause algae problems?
> if as you state the plants adjust to what ever light is offered them, then it stands to reason that a change of lighting would cause a further adjustment in the plants which may "stall" or slow growth.


As Dan's experience attests, no, it would be a very bad assumption to conclude that a spectral change causes algae. Spectral changes occur throughout the day, and the plant has a multitude of, what's called, "Auxiliary Pigments" to absorb those wavelengths that the chlorophyll molecules are not optimized around, so the transition is seamless. It can be that perhaps a new bulb(s) has a higher intensity than the old one(s), for example, and that if CO2 or dosing is marginal, the higher energy is not accounted for. So this might give the illusion of a spectral change causing problems, if any.

Cheers,


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## firstman (7 Oct 2009)

aaronnorth said:
			
		

> Is it fact or myth that actinic lighting promotes algae growth?



Clive, I have read what you have said on this subject and have sent PMs back and forth with you in the past. So I am aware of what you are saying and agree with you. But the rest of the world isn't ready for this. I'll explain. 

I just want to tell everyone about my recent experience trying to explain this exact thing on another forum. Let's just say that I wasn't welcomed with open minds and hearts. There was a post about someone buying a Current Satellite Dual light fixture asking if it was a good setup. The response was that they needed to replace the dual 10,000k/420nm bulb because Actinic induced algae. So I responded with the fact that 420nm fell right inside the blue peak in the Chlorophyll Absorption Spectrum and that algae was induced by many things such as ,low/fluctuating CO2, low nutrient levels, poor circulation, but not Actinic. I even put links up to the info on algae to Barr Report supporting what I was saying about 'low' nutrients and not 'excess' nutrients causing algae.You know the drill. This is when the fun started. 

This guy told me that I had no idea what I was talking about and that I needed to research before I went to forums giving "horribly bad advice to people" and how he has been "a Horticulturist for twenty years and knows more about light than I will ever know". He then proceeded to tell the OP that the higher the K rating is on a bulb the greater the chances of algae were and that light in the green spectrum was the most effeciently used by plants.  WHAT!?! 
I informed him that green light is 'reflected' and therefore is not utilized by plants. I  even put up a Chlorophyll Absorption Spectrum file to show how this was an error. His response to me was, well, lets just say the moderator deleted it from the forum. 

So I went on with my business on the forums and found another post about Actinic bulb needs to be removed and replaced with another bulb. I said, "technically the 420nm bulb can be used. The light falls well within the 'visible' spectrum that plants use for photosynthesis,and coincidentally, is the same light that our eyes use as well. And gave a link to this info stating exactly what I had said. 
'Visible light is the range of wavelengths of the electromagnetic spectrum that humans can see, a mixture of wavelengths ranging from 380 nanometers (def) to 760 nanometers. It is this light that is used in photosynthesis.' 
Found this here: http://student.ccbcmd.edu/biotutoria...syn/photo.html

That same guy responded. His message was only 'edited' by a moderator this time. He stated that plants don't just use the 'visible' light as we do, but they use UV as well.  

So I posted this:
'UV on the other hand has too much energy, and in a sense can't be controlled by plants. UV light intercepted by plants (and us) can create free radicals, which can break chemical bonds in an organism. This is detrimental to the plant. Plants in fact have pigments to protect them from UV light.'
Here: http://www2.mcdaniel.edu/Biology/bot.../l2inature.htm

Anyway, to make a long story short. No matter how much info you give to someone, they are going to regurgitate the same old info that they have been spouting forth for years with a closed mind.


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## aaronnorth (7 Oct 2009)

I hate it when people go against, quite obvious, and proven information such as UV light cant be used for plant photosynthesis.


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## Dave Spencer (7 Oct 2009)

firstman said:
			
		

> This guy told me that I had no idea what I was talking about and that I needed to research before I went to forums giving "horribly bad advice to people" and how he has been "a Horticulturist for twenty years........



This type of statement above annoys me from time to time. I have been playing tennis longer than Roger Federer....does he come to me for advice on his dodgy back hand?  

Out of interest, which forum was it?

Dave.


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## ceg4048 (8 Oct 2009)

The Matrix is all around us. You can see it everywhere you go - when you go to church, when you pay your taxes. It's a world fabricated to hide the truth. 
Unfortunately, no one can be told what The Matrix is. You have to see it for yourself. Those who are addicted to their connection to The Matrix will fight to the death to defend it. It's specifically constructed that way. Only when one has been disconnected can the truth be seen clearly.

Learn as much as you can and master your craft, implementing what you've learned. That's the most that you can do. If some decide to follow your lead then they are the lucky ones. As for the rest, well, they'll just remain imprisoned in an embryonic state having chosen to learn nothing - and will be quite happy about it. Leave them and don't disturb their happiness.

Cheers,


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## baron von bubba (8 Oct 2009)

Dave Spencer said:
			
		

> I have been playing tennis longer than Roger Federer....does he come to me for advice on his dodgy back hand?
> Dave.



nice!


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## firstman (8 Oct 2009)

Dave Spencer said:
			
		

> firstman said:
> 
> 
> 
> ...


 
www.plantedtank.net


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## firstman (8 Oct 2009)

ceg4048 said:
			
		

> As for the rest, well, they'll just remain imprisoned in an embryonic state having chosen to learn nothing - and will be quite happy about it. Leave them and don't disturb their happiness.
> 
> Cheers,



I hope they get algae.     

I'm sorry. That's not right. Bless me Father for I have sinned. And bless all the Pigmies in New Guinea. Amen.


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## Mark Evans (8 Oct 2009)

Dave Spencer said:
			
		

> This type of statement above annoys me from time to time



me too. i went a particular forum, trying to educate, but no! they wouldn't have it. same old crap info flying around. oh well, you cant educate pork as they say.


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## firstman (8 Oct 2009)

saintly said:
			
		

> me too. i went a particular forum, trying to educate, but no! they wouldn't have it. same old crap info flying around. oh well, you cant educate pork as they say.



Tell me about it. This is why I use this forum. Not only do the people on this forum not just follow blindly the rumors and speculation, but you treat eachother with respect and truly care about furthering this great hobby of ours.


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## CeeJay (9 Oct 2009)

Hi


			
				firstman said:
			
		

> Not only do the people on this forum not just follow blindly the rumors and speculation, but you treat eachother with respect and truly care about furthering this great hobby of ours.


I couldn't agree more.   

Chris


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## paul.in.kendal (9 Oct 2009)

chrisr01 said:
			
		

> Hi
> 
> 
> 
> ...


[Paul piping up from Cumbria] - me too!


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## Mortis (9 Oct 2009)

Some of these guys remind me of Apple fanboys lol.

If you look at it logically and use some of the science you learnt in school it would be quite obvious that out of the 3 primary colours of light (red, blue & green) plants would prefer red and blue lights because they can only absord those two and not green which they would reflect.


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## ceg4048 (10 Oct 2009)

Mortis said:
			
		

> .. they can only absord those two and not green which they would reflect.


This is not entirely true. Plants use all visible wavelengths depending on the environmental conditions. Let's not compound one myth with another.

Cheers,


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## Mortis (10 Oct 2009)

Yeah, your right I guess. Plants just use the photons from light for photosynthesis right ?


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## ceg4048 (11 Oct 2009)

Mortis said:
			
		

> Yeah, your right I guess. Plants just use the photons from light for photosynthesis right ?


Correct! The mechanism of photon assimilation is summarized in the thread PL-11 Tubes 

More details about spectral quality in the thread Bit lost in the Luminaire Jungle and Looking for neutral colour T8 tubes

If one is worried about algae, it'd be a better idea to forget about spectral issues completely and concentrate more on understanding the principles discussed in the thread Why don't nutrients cause algae? because it's almost a certainty that the people who are programmed by The Matrix to worry about spectral quality have also been programmed to worry about nutrients. A diabolical combination of misinformation. I advise to take the Red Pill...

Cheers,


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## Mortis (12 Oct 2009)

Yay ! But plants do prefer light in the blue/red spectrums right ? Are the photons in a 'better' energy state at these wavelengths ?


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## ceg4048 (12 Oct 2009)

Well it's not good to think in terms of "better", otherwise we fall into the same trap as our brethren trapped in The Matrix. Blue and red are the fundamental frequencies. Blue is so abundant and has high energy levels so the plants use a system of blue sensors, called Cryptochromes, to control things such as chlorophyll synthesis, stomatal opening and even phototropism (the direction of growth, or the tracking of the light).

Red is used for various other sensor data. This is referred to as Phytochrome system. Phytochromes are proteins which respond to incident red. Phytochromes have their own special pigments called chromophores, and they change their protein structure based on the specific wavelength of the red. Different responses occur based on the type of structural change of the protein. For example the level of red can tell the plant whether it's in shade and the degree of shading to which an individual leaf (or the plant as a whole) is subject to. So this governs response and behavior, even optimization of nutrient uptake mechanisms. As a result of this sensor data, there will be specific conformational changes such as elongation of stem, leaf shape change and so forth.

So you see it's not a matter of "better" or "worse"... that's an illusion. It's simply a mater of how individual species allocate their resources in response to the environment based on the light provided. If you decide that you love looking at a pink tank then use 100% Grolux type lights and the plants will make the adaptation based on what they sense and will reallocate their resources to match the Grolux. If you decide that you prefer Marine Actinic, or Daylight, or a combination, then the same will occur. As long as you are above the LCP and are providing adequate levels of CO2 for the given photon flux density, the adjustments will be made. Remember that auxiliary pigments have the ability to change the incident wavelengths by absorption and fluorescing. This is easily done by adjusting the energy levels of electrons within the pigment structure.

I can grow plants just fine using standard office bulbs which have most of their energy in the yellow/orange. Osram 840 is a classic example. Here is L. aromatica grown pretty much with these goofy orange bulbs until I couldn't stand it any more. All it does is make everything look orange. What's the big deal?





Here is some more grown with a combination of blue and daylight. I don't see any algae due to blue:




If you want to use the word "optimum" then sure, make sure you have at least some of the fundamental frequencies blue/red, but don't stress over spectral quality. There are so many other things that will have a palpable effect on growth that spectral quality "pales" in comparison. 8)

Cheers,


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## plantbrain (13 Oct 2009)

I've used 50/50 Atins and daylights, they look ugly as Hades.......

They do not really affect any algae or plant growth compared to other lighting.

That's the practical test.
For the theory to be correct, I'd have to see some evidence that they do encourage algae in and of themselves, not due to these bozo clowns on the web who cannot grow plants consistently day to day, who know what caused their algae issue/s?

May have simply been more intensity when switching to Pc lights etc, or newer bulbs etc, nothing to do at all with the spectrum etc. They never demonstrate that nor provide a control for all their banter and rubbish.

They either poo poo the criticism via PM's, or something they are foolishly brave enough to try and justify they have actually demonstrated something and try to argue that. I think the latter is worse.

Socially it is understandable.
Who likes to be told that their myth based advice is wrong and false?
So they often do not go down without a fight :idea: 

This is a bit of human nature.
Many stories surround this conflict's theme.
Myth,belief vs the the logical common sense.

I find some BS I've been telling folks is wrong, I go back and make sure, learn more, see if and how I went wrong. Learn and correct it. We all make mistakes, admit it and learn and move on dangit!

Or ye shall be flogged with Cattails till ye howl like the vermin that ye are.  

Heck, you only make your self better in doing so, and you help your fellow hobbyist.

I do think there is somethings to be said for different colors of bulbs and getting certain aesthetics from the lighting.
I have much better coloration in my T5 tank vs the others with MH's and PC's. PAR's are about the same, a little difference in spread etc. I cannot attribute it to much else other than color. These aesthetics however, much harder to quantify and too find any good research answering such aesthetics based questions.

Rats......



Regards, 
Tom Barr


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## Lisa_Perry75 (13 Oct 2009)

In strong white light plants can utilise green light for photosynthesis better than red or blue.

http://pcp.oxfordjournals.org/cgi/content/full/50/4/684


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## sanj (23 Nov 2009)

Thanks for this thread, I am due to move aquarays from my Reef to subtitute some T5 lighting on my planted tank (new LEDs going on the Reef tank). So i was wondering about blue light and thought that plants should be able to utilise and adapt to bluer light from Marine whites, Reef Whites and blues, just that it may not look too good. Then again they would be mixed with T5 6000k so might not look too bad.

Yes there is a lot more Blue light/Actinics grow algae on the net. I would think that would be if they were using blue lights for long periods of time outside the photo period. Hmm...

Clive excellent understandible reasoning as usual. How is the book coming along? You know you should.


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## ceg4048 (23 Nov 2009)

Yeah, I know, but I'm still stuck on what the title ought to be. I'm thinking something like "Blue Haters & Nutrient Haters - Push Off".   

Cheers,


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## plantbrain (24 Nov 2009)

Lisa_Perry75 said:
			
		

> In strong white light plants can utilise green light for photosynthesis better than red or blue.
> 
> http://pcp.oxfordjournals.org/cgi/content/full/50/4/684



ADA's lights are mostly in a green band also.

Reflectance also plays an aesthetic role to our eyes.
Hard to tease those apart for our goals.
I do not think the algae cares much as long as there's some 400-700nm range available.
Same for plants.

Regards, 
Tom Barr


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## AndyOx (28 Nov 2009)

ceg4048 said:
			
		

> Yeah, I know, but I'm still stuck on what the title ought to be. I'm thinking something like "Blue Haters & Nutrient Haters - Push Off".
> 
> Cheers,



I like it


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