Questions regarding RGB Lighting

Nick72

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Thank you all.

So the consensus:

  • Blue light should have no specific impact on algae growth in a freshwater planted aquarium.
  • Increasing blue light (or any other colour) settings will naturally increase overall light intensity which may increase algae growth.
  • Blue light has a shorter wave length than other colours, so a 10% increase in blue light may have a bigger impact on overall light intensity at substrate than a 10% increase in an alternative wave length.

I still wonder why of the three default settings offered by Fluval for the Plant 3.0, two have blue light set to zero, and Planted has blue light set to 20%. All other wave lengths are set between 75-100% across all defaults.

Is this purely because they believe these settings provide the most natural look to the human eye, or is there another reason they are being so lean on blue?


Hi @Nick72

It would make sense to me that you may need to carefully consider the amount of blue light entering a tank. That's because white LEDs start out life as blue LEDs. This blue light passes through a phosphor inside the body of the LED. The phosphor fluoresces re-emitting white light composed of blue, green and red light in this order of intensity. To this light is then added more blue from the blue emitter in the RGB LED. And this RGB LED also emits green and red light, of course. But, the combination of a white LED and an RGB LED seems to result in more blue light than either green or red light. I'll see if I can dig out some typical spectra to further illustrate the points that I'm trying to communicate in words. But, that's for tomorrow.

JPC
@jaypeecee - You say this because adding more blue light will look unnatural? Or for another reason?
 

Geoffrey Rea

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Dennis Wong’s site is a good port of call for a bit more reading on lighting spectrum and mixing:

https://www.advancedplantedtank.com/blogs/beginners-planted-tank-101/best_light_spectrum

I still wonder why of the three default settings offered by Fluval for the Plant 3.0, two have blue light set to zero, and Planted has blue light set to 20%. All other wave lengths are set between 75-100% across all defaults.
Best guess @Nick72 would be unless you have plants under their unit, the additional blue would just add unnecessary deeper penetrating short wave blue light to the bottom of the tank. Diatoms would appreciate it but if no plants are using that light to photosynthesise, then algae would potentially be an issue in a fish only setup.

People may buy the Plant 3.0 because they enjoy the colour rendition it gives their fish without necessarily intending to grow plants.
 

jaypeecee

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@jaypeecee - You say this because adding more blue light will look unnatural? Or for another reason?
Hi @Nick72

I say it not for aesthetic reasons but because excess blue light could encourage algae. I'm also suggesting that there may be an excess of blue light for the reasons I tried to explain above. BTW, I don't quite understand your first two bullet points in post #22 above. They appear to contradict each other. But it may just be my interpretation.

@Geoffrey Rea has raised a very important point about the depth of light penetration in water. At depths up to 90cm, the reduction in both blue and green is negligible but reduction in red at 660nm is 75% (i.e. down to 25%). And, at 60cm, red would reduce to 50%. Therefore, the light being emitted from the lighting fixture needs to take this into account. My hunch is that many manufacturers of aquarium lighting do not consider these details.

JPC
 

Nick72

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.......
Best guess @Nick72 would be unless you have plants under their unit, the additional blue would just add unnecessary deeper penetrating short wave blue light to the bottom of the tank. Diatoms would appreciate it but if no plants are using that light to photosynthesise, then algae would potentially be an issue in a fish only setup.
......
Hi @Nick72

I say it not for aesthetic reasons but because excess blue light could encourage algae. I'm also suggesting that there may be an excess of blue light for the reasons I tried to explain above.

....JPC

OK. From your early posts and having read the article by Dennis Wong I was coming around to the concept that Blue light has no appreciable effect on algae beyond that light of any spectrum at too high an intensity can contribute.

In fact I've just raised my blue light to 15% and taken 25% off a combination of white lights to compensate for overall intensity.

But in both of your posts above you are now suggesting that excess blue light can contribute to algae and diatoms.

It feels like a mixed message to be honest.

I was just considering, if blue light does not stimulate algae growth, why I might not increase my blue light to something much higher, say 50%.

I think that might help colour rendition, where my greens are yellow-ish, would not additional blue create a better green.

But your last two comments have given me pause.
 

Nick72

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....BTW, I don't quite understand your first two bullet points in post #22 above. They appear to contradict each other. But it may just be my interpretation......


Point one states that Blue light is no more of an algae stimulator than any other spectrum.

Point two states increasing any light spectrum to the point of excess intensity will stimulate algae growth.

I could probably have phrased it better the first time, but no I don't believe they contradict.
 

jaypeecee

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Hi @Nick72

I'm not sure how to clarify things any further. Perhaps I'm losing my written communication skills. I'll re-visit this thread at a later stage to see if there's anything we can do. It's a complex subject and being able to communicate with words would help but that's not practical.

JPC :)
 

Nick72

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Hi @Nick72

I'm not sure how to clarify things any further. Perhaps I'm losing my written communication skills. I'll re-visit this thread at a later stage to see if there's anything we can do. It's a complex subject and being able to communicate with words would help but that's not practical.

JPC :)

Sorry @jaypeecee - I'm not trying to be difficult.

I've just read this thread again from top to bottom.

Actually you never stated that Blue light does not cause algae, if anything you say that it can. So sorry if I misrepresented you.

I also do completely take your point that white LEDs are biased towards the blue spectrum.

But until the last couple of posts which I highlighted (yours included) every previous post had stated that Blue light categorically does not promote algae growth.

So those last couple of posts threw me.

I sincerely appreciate everyone's input, just wish the answer was more clear cut.
 

jaypeecee

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Hi @Nick72

No problem, my friend. Now that we've cleared up any confusion/misunderstanding, we can pursue this further if you wish.

JPC
 

jaypeecee

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Hi @Nick72 & Everyone,

There's one other thing that I failed to mention about blue light and that is - it shrinks plants! You may want to look at the following in which Dr Bruce Bugbee talks more about this. I don't know how I managed to forget this but so be it. Here's the video:


I have referenced this video before on UKAPS.

Dr Bugbee generally refers to terrestrial plants. I don't know to what extent his statements apply to aquatic plants.

JPC
 

cbaum86

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Hi @jaypeecee

Sorry, maybe I missed something in one of your earlier comments or links. I know you don't say that blue light causes algae you state it could, but I'd be interested to know why.
  1. Is it something to do with the actual wavelengths in the blue part of the spectrum have an impact on some particular biology which stimulates the algae grow more than it would with another colour?
  2. Is it because the blue light has the ability to penetrate deeper into the aquarium. So if you had a shallow tank with red LEDs is there just as much impact on algae growth as a deeper tank with blue LEDs for example?
  3. Is it that blue light in itself does not cause algae but more the fact there is a chance of excess blue light in a lot of fixtures because of the combination of white and blue LEDs. So any excess of light will cause algae, it's just in the majority of cases this happens to be blue.
  4. Something else or a combination?
Also, is all algae the same in terms of light reaction? I know Darrel made a comment earlier about potential difference between red and green algae.

Apologies, I may have butchered some of the understanding on the topic but I like to try understand things a little better and try to ask the right questions so I can at least make what I think is an informed opinion on the subject.

Thanks,
Chris
 

jaypeecee

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Hi @cbaum86
Sorry, maybe I missed something in one of your earlier comments or links. I know you don't say that blue light causes algae you state it could, but I'd be interested to know why.

Is it that blue light in itself does not cause algae but more the fact there is a chance of excess blue light in a lot of fixtures because of the combination of white and blue LEDs. So any excess of light will cause algae, it's just in the majority of cases this happens to be blue.

Also, is all algae the same in terms of light reaction? I know Darrel made a comment earlier about potential difference between red and green algae.
Hi Chris,

Firstly, I am just someone who has read extensively on the subject of plant lighting. A lot of the time, that means turning to horticulture where there is the commercial need to use every photon of light efficiently. And my understanding is that Dr Bugbee (above) has done a lot of work for NASA to enable crops to be grown on the ISS. Unfortunately, there doesn't appear to be much similar work taking place on aquatic plants. I guess if the likes of Tropica and Aquafleur were growing submerged aquatic plants, things might be different. But, it would appear that most plants destined for our tanks are grown emersed. In summary, I consider myself to be an enthusiastic amateur in this field but I'm no expert.

Anyway, in answer to your question, you will see that I have highlighted your post (in blue!) the option that I believe to be the case. I would, however, prefer to say that 'any excess of light may cause algae'. If you haven't yet visited Dennis Wong's web site, here's a good starting point:

https://www.advancedplantedtank.com/blogs/light-3pillars

JPC
 
Last edited:

cbaum86

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Thanks @jaypeecee.

I like to think I'm gaining a better understanding of these things and in a debate it's always helpful to use my own informed opinion with some understanding rather than just say "because so-and-so on X forum said so". Much more convincing an argument to be able to say "I think X because of Y and this group of so-and-sos have similar experience/thoughts". Although like you say, I find there is a lot of information we have to imply to the aquatic side based on terrestrial info/studies.

I've previously seen some other videos from Dr Bugbee that were very interesting but I'm always cautious to correlate that directly to our aquatic plants - still it hasn't hurt me doing so so far.

I would, however, prefer to say that 'any excess of light may cause algae'.
A very good point. Need to be careful with the wording.

If you haven't yet visited Dennis Wong's web site, here's a good starting point:
I've been referencing the site for the past year or 2 now, great resource. Struggling to find everything I remember reading on the new layout though.

Cheers!
 

dw1305

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Hi all,
I know Darrel made a comment earlier about potential difference between red and green algae.
The Green Algae (Chlorophyta) are the basal group to all the green plants (together they form the clade <Chlorobionta or <"Viridiplantae">) and <"share a common ancestor">, from which they all inherited the same <"basic physiology and photosystems">.

tree.jpg


In terms of photosynthetic pigments, and light interception, there are only very minor differences between any of the members Viridiplantae clade. If you like what is "sauce for the goose is sauce for the gander".

<"Cyanobacteria, Red Algae (Rhodophyta) and Diatoms"> are much more distantly related to all the green plants.

cheers Darrel
 

jaypeecee

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Hi @dw1305 / Darrel

The link immediately above (Cyano...Diatoms) doesn't appear to be working for me. I take it that it works for you?

JPC
 

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