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Light colour & algae

idris

Member
Joined
3 Jan 2011
Messages
816
Location
Herts
Is there any colour light that is less prone to helping algae? Without working things out scientifically, I'm wondering about purely green light (as I think that what's reflected from green leaves... right?)
As much as anything I'm hoping to extend the time I can watch my tank without it causing algae growth.
 
I think its more to do with a balance of your lighting than this light or that light to avoid algae. I always use cheap t5 ( see James C in lighting)tubes and recently budget end nicrew eg LED lights . Seen quite a few examples of more expensive lights with just the same algae issues. Low energy aquariums can have and better for it long photoperiods. Use floating plants is good way to go.Personally go for a pleasing light to your eye.The question about greens and lighting is a technical one. One of our lighting gurus might help
 
I agree with paraguay. There is no color you can use that will avoid algae. Algae is cause by too much light intensity of any and all colors. If the intensity is low enough then the lights can be on for a long time.

Having said that you can give yourself more room for error with bulbs that do have a high green and yellow content. The old ADA bulbs (the NA bulbs) are very high in green/yellow which made the tank look bright to human eyes but were still had a low PAR output. There were (and probably still are) however, ridiculously expensive.
It's probably better to simply use the old school T8 fluorescent bulbs which doesn't cause much trouble. That's what folks used long ago and rarely suffered as much of these algal blooms. We now have access to LED fixtures which have wattage ratings which seem quite low by comparison - but folks simply do not realize how much more aggressive light intensity is produced for very low wattage.

Cheers,
 
Are cheap, domestic/ ebay (green / RGB) IP65 LED strips relatively "intense" compared to aquarium specific LEDs. My gut says they ought to be less "intense". But I've no idea how 1hr with something like that would compare with an hour of my iQuatics T5s.
(Throw in a PWM driver from something like an Arduino clone and ... well ... I'm ar least partially out of my depth. I have some components lying around, but no PAR meter.)
 
Few have any idea, without an objective measuring device, which unit has higher intensity, whether labeled as aquarium specific or otherwise.
Without a PAR meter much of what you see, or much of what you think you see...can easily be an illusion.
More importantly, the advantage of an LED, as long as you spend enough money, is to have a dimmer. If you're a good DIYer then you can cut the wires and assemble it to your own dimmer.

Cheers,
 
Many types of algae can use green light, Rhodophyta en Cyanobacteria have phycobilisomes to catch that part of the spectrum. That is why they don't appear to be green.

If you change your lightning algae usually appear, but with proper maintenance (cleaning the algae away) and care (fertilizing the plants) plants will adapt and make algae disappear again. I light my tanks for 10 - 12 hours a day, because I don't like looking at a dark tank. I have massive outbreaks of algae 7-10 days after setting up a new tank, less light (lower intensity/shorter period) will slow the growth rate of algae down and make it more manageable for sure, but after a few weeks things will improve when plants start growing and take over. In my experience it does not matter if you have low or high light, low or high co2, full EI or lean dosing, as long as you keep the levels consistent, given time plants will beat the algae.
 
Many types of algae can use green light, Rhodophyta en Cyanobacteria have phycobilisomes to catch that part of the spectrum. That is why they don't appear to be green.
That is true and plants also use green light because they have the same light gathering proteins as algae and cyanobacteria. In fact, green light is used in conjunction with the other wavelengths to deliver those photons deeper which allows these proteins that are below the surface to obtain more light.

The fact that Rhodophyta and Cyanobacteria are capable of using green should NOT be construed to mean that if your light has green this will cause algae.

Cheers,
 
That is true and plants also use green light because they have the same light gathering proteins as algae and cyanobacteria. In fact, green light is used in conjunction with the other wavelengths to deliver those photons deeper which allows these proteins that are below the surface to obtain more light.

The fact that Rhodophyta and Cyanobacteria are capable of using green should NOT be construed to mean that if your light has green this will cause algae.

Cheers,

Well the proteins in plants and algae are not all exactly the same, Chlorophyll A is universal but the other types of chlorophyll are not. Phycobilisomes and the proteins they are made of are restricted to certain types of algae and cyanobacteria. Other chemicals like carotene and xanthophyll are found in both but not in all. So there are some differences, but the end result is very similar. And not relevant for our purposes at all.

it is indeed a widespread misconception that plants will grow better if provided with light in the wavelengths they can absorb best. this is not true, it is only more energy efficient (to some extend)
 
So more PAR is good for plant growth.
As I can't justify a PAR meter for purchase of a single light, is there any way to find low PAR lighting? (I can build an LED dimmer far more cheaply.) Every light I've seen advertised that mentions PAR seems to be sold on the basis of being good for plant growth, as opposed to good for evening viewing without plant (or algae) growth.
Or am I still missing the point?
 
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Hi all,
Every light I've seen advertised that mentions PAR seems to be sold on the basis of being good for plant growth, as opposed to good for evening viewing without plant (or algae) growth.
You can definitely use a dim light for tank viewing without getting anywhere near light compensation point (LCP) for any photosynthetic organism, plant or algae. Our eyes are really good at adjusting to low light levels and <"subdued room lighting is only 100 to 200 lux">.

cheers Darrel
 
So more PAR is good for plant growth.
As I can't justify a PAR meter for purchase of a single light, is there any way to find low PAR lighting? (I can build an LED dimmer far more cheaply.) Every light I've seen advertised that mentions PAR seems to be sold on the basis of being good for plant growth, as opposed to good for evening viewing without plant (or algae) growth.
Or am I still missing the point?
It's exactly as Darrel mentions. LCP is a very low energy level and more PAR does not mean "better" growth. It simply causes "faster" growth. There are plenty of tanks using too much PAR where the rate of growth is fast, but the health of the plants is poor. Conversely, there are plenty of tanks lit with low light where the plants are very healthy. People very often confuse "fast" with "better".

Cheers,
 
...it is indeed a widespread misconception that plants will grow better if provided with light in the wavelengths they can absorb best. this is not true, it is only more energy efficient (to some extend)...

Hi @akwarium

I'd be very interested in knowing more about this. From what I have read, it seems that action spectra and absorption spectra are closely correlated. And, since action spectra are quantifying photosynthesis activity by measuring oxygen released from a plant, would this not correlate with plant growth? Doesn't the rate of release of oxygen from a plant correlate with plant growth rate? Am I barking up the wrong tree?

If I'm not making myself clear, just say and I'll have another stab at this.

JPC
 

1634383221432.jpeg


plants can grow pretty fast in the dark though one might not say its 'healthy' growth. I've seen it happen when I did a 72-hour blackout. Fast growth of some stem plants and aerial roots popping out. I've read of some terrestial plants when they are shaded by other plants they try to grow as tall as possible to get sunlight, not sure if thats the explanation for growth during blackout periods as well.

As for the topic light spectra and photosynthesis, I found Bruce Bugbee's youtube videos absolutely fascinating (and of course, I have to credit UKAPS for introducing me to them)
 
Hi @akwarium

I'd be very interested in knowing more about this. From what I have read, it seems that action spectra and absorption spectra are closely correlated. And, since action spectra are quantifying photosynthesis activity by measuring oxygen released from a plant, would this not correlate with plant growth? Doesn't the rate of release of oxygen from a plant correlate with plant growth rate? Am I barking up the wrong tree?

If I'm not making myself clear, just say and I'll have another stab at this.

JPC
yes you are right.
But there are some remarks to be made, (note I'm just a hobbyist so by no means an expert)
Firstly plant growth is often looked at as the result of photosynthesis and therefor there is a focus on the absorption spectra of chlorophyll a and b.
That does not take carotenoids in account, which will also harvest energy. Or Phytochromes which are most sensitive to deep and far red light and have a significant impact on how a plant grows and looks. (and are an important factor why plants stretch during a blackout)
Secondly there is a big difference between absorption of a single chlorophyll molecule and an entire leaf with several layers of cells all filled with chloroplasts, and entire plants made of several layers of leafs. a leaf or plant can absorb 70% or even more of the green light, most of the red and blue will be absorbed in the top layers, but the green light penetrates deeper into the leaf tissue or canopy. There it will hit many more molecules of chlorophyll that will absorb it bit by bit.
Lets not forget that once absorbed any photon is the same. The entire spectrum between 400 and 700 nm is called Photosynthetic Active Radiation, because it is. Although red and blue's are absorbed to a higher degree then the colors in between, the difference is smaller then often assumed and lower leafs and chloroplasts deeper into the leave tissue might actually rely for most of there energy on greenish light.
So using only red an blue light will mean that more of the light produced is also absorbed and converted in carbohydrates, which makes it more energy efficient. But for normal, good looking and healthy plants, a full spectrum seems to be preferable.
 
Hi all,
yes you are right.
Good explanation and better than I could manage.
From what I have read, it seems that action spectra and absorption spectra are closely correlated. And, since action spectra are quantifying photosynthesis activity by measuring oxygen released from a plant, would this not correlate with plant growth? Doesn't the rate of release of oxygen from a plant correlate with plant growth rate? Am I barking up the wrong tree?
Yes, oxygen release correlates very closely with CO2 incorporation. This is because for every molecule of CO2 that enters photosynthesis a molecule of oxygen (O2) is liberated. Plants are made of a carbon skeleton, and their growth is a measure of the net difference between CO2 absorbed and oxygen liberated.

This net difference allows all <"aerobic life on earth"> to survive (and to initially develop).

799px-Photosynthesis_equation.svg.png


cheers Darrel
 
So using only red an blue light will mean that more of the light produced is also absorbed and converted in carbohydrates, which makes it more energy efficient. But for normal, good looking and healthy plants, a full spectrum seems to be preferable.
Hello,
This is not really true. You do not need full spectrum at all. This is the misconception that allows vendors to charge outrageous prices for their so called "full spectrum" bulbs. Plants have the ability to change the color of the incident light into other colors to fit their needs. Discussed and argued in the thread containing the post=> Fundamentals of Aquatic Lighting

We allow ourselves to be fleeced by the vendors because of our tacit agreement that spectrum is more important than it actually is. Hobbyists never really study this subject because it's a very difficult subject. As a result, we simply accept the opinions of the majority of others. The problem is, no one has actually ever proven that any "full spectrum" bulb grows plants any better than an ordinary bulb found in a supermarket or office building. Folks just assume that the majority opinion is correct without any data to show for it. In effect, might=right.

Was anyone aware, for example, that ADA bulbs were never "full-spectrum"? In fact, the bulbs are extremely high in green. So much so that the fluorescent bulbs actually have the model name "NA Green". No one argues the growth rate and health of their gallery tanks, yet, no one has ever questioned why their bulbs are not "full spectrum". Their tanks are low light because, as you mentioned, the green, although delivering lower PAR than blue, penetrates deeper into the tissue allowing it to reach the chlorophyll cells located further beneath the surface, thereby improving the quantum yield.

Cheers,
 
Hello,
This is not really true. You do not need full spectrum at all. This is the misconception that allows vendors to charge outrageous prices for their so called "full spectrum" bulbs. Plants have the ability to change the color of the incident light into other colors to fit their needs. Discussed and argued in the thread containing the post=> Fundamentals of Aquatic Lighting

We allow ourselves to be fleeced by the vendors because of our tacit agreement that spectrum is more important than it actually is. Hobbyists never really study this subject because it's a very difficult subject. As a result, we simply accept the opinions of the majority of others. The problem is, no one has actually ever proven that any "full spectrum" bulb grows plants any better than an ordinary bulb found in a supermarket or office building. Folks just assume that the majority opinion is correct without any data to show for it. In effect, might=right.

Was anyone aware, for example, that ADA bulbs were never "full-spectrum"? In fact, the bulbs are extremely high in green. So much so that the fluorescent bulbs actually have the model name "NA Green". No one argues the growth rate and health of their gallery tanks, yet, no one has ever questioned why their bulbs are not "full spectrum". Their tanks are low light because, as you mentioned, the green, although delivering lower PAR than blue, penetrates deeper into the tissue allowing it to reach the chlorophyll cells located further beneath the surface, thereby improving the quantum yield.

Cheers,
I did not say you need full spectrum. I only said it seems to be preferable compared to only blue and red. RGB is by no means full spectrum and still grows very nice plants. For me any ordinary white LED is full spectrum enough (although they usually have very little violets, deep blues, cyan and reds, so technically it might not really be full spectrum)

for the past 6 years I use self made led lamps with one or more types/colors of good quality leds. I experimented with adding 660nm reds, it should help aquarium plants to grow more compact, and maybe it does, but under the total amount of light plants will grow compact anyway, so I don't think it is really worth the trouble. (it does give a nice sunrise though). I used 730nm far red to see if the emerson effect would speed up plant growth, I do think it had some effect. but the tank was quite dimly lit, In terms of energy efficiency maybe it was doing quite well, but unless you like a cheap brothel look, the esthetics were awful.

And aquarium lightning is not about maximum yield with a high energy efficiency, it is about esthetics. Since aquatic plants are not light demanding at all compared to most other plants and crops, just get a light that makes your tank look goed and your plants will probably be fine. I enjoy all the discussions about spectra, and love reading about it, trying things for myself. Good fun, but practically a complete waste of time.
 
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