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Spectrum...doesn't matter...does it?

Tim Harrison

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I've been reading on this forum for some time now that spectrum doesn't matter. I'm not entirely sure what this means.

I can't be the only one who is struggling with this so I think it would be a great help if we could pin it down to a precise explanation.
 
Yeah. I think Clive mentioned that the plants don't care what type of light, as long it is visible to the naked eye. Kelvin doesn't matter.

Question for Clive:
Does it matter if it's marine actinic light or Arowana tanning light??
 
Thanks guys...of course I value Clive's knowledge and opinion but I also value that of others too, so if you have any thoughts I'd love to hear them...Then maybe we can get some sort of discussion going - which is something this forum does particularly well.
 
I think you might have to be more precise about what it is you don't understand about the previous discussions. Or what it is you don't agree with and why. I hope that doesn't sound abrupt but put some meat on the bone, lol
 
I think the theory that certain kelvin ratings cause problems in planted tanks is so deep seated among aquarists, it's difficult to accept otherwise. To take the word of one man over thousands of others saying the opposite is not an easy thing to do, especially when you believed the thousands in the past.

I prefer a warmer light in my tanks, and so avoid actinics like the plague anyway.
 
Id it doesn't matter, why have manufacturers like TMC made such a think about making their growbeam range specifically at the 6500K range ? Why would they not just make LED's at a range of temperature levels if its purely an aesthetic thing ?
 
I'm one of those people that claim that plants aren't fussy about spectrums.

Sorry, I can't prove it through experimental data, but I can say I've probably tried over 50 types of lighting over the years with varying spectrums and can't say one is better than the other. This is why my lighting choice is now purely based on aesthetics (colour rendition as well as the unit design) and cost (initial purchase and running cost).

It wouldn't surprise me if plants readily adapt the whatever spectrum is present. I think most plants we grow are aquatic weeds that are very opportunistic and able to utilise what's available. This principle also applies to nutrient levels, as we know.

IWhy would they not just make LED's at a range of temperature levels if its purely an aesthetic thing ?
They do. The Colour-Plus tile is now marketed under the GroBeam range because TMC realise it grows plants very well too, as does the marine 1500XG tile (9000K).
 
I've been reading on this forum for some time now that spectrum doesn't matter. I'm not entirely sure what this means.

I can't be the only one who is struggling with this so I think it would be a great help if we could pin it down to a precise explanation.
Hey Troi,
I believe this is a cleverly constructed trick question specifically designed to see who's been paying attention.

However, I have solved the riddle:
You have in fact, NOT been reading that spectrum doesn't matter, or that there are no effects of spectrum. What you've reading is that spectrum has negligible effects on plant growth rate and overall health.

There are a multitude of effects of spectrum, but those effects have little to do with whether you should worry about or be restricted to only using a specific color for the sake of the health of your plants.

In any case, there is plenty of talking about spectrum ad nauseum, but I notice that there are very little actual doing. You can answer this question yourself by simply using a specific color bulb on newly bought plants and record their growth with images, say for 8 weeks. Then repeat using a different color bulb. You can even go as far as to weigh the plants at the beginning and at the end of the test period to record the mass increase. Pick an easy plant, and purchase each batch from the same vendor to eliminate effects of inconsistent quality. Then repeat using a different plant. Note the results.

What you'll discover is that the thousands of people who say there is an effect on growth and health are all say this because they saw where someone else said it. The few people who say there is NO effect on growth and health are people who actually have tried it.

As far as any other effects of spectrum, well the effects can be very interesting, but not vital.
Example of a spectrum effect I quote from another post:
It turns out that as light enters water, different wavelengths with different "energies" will penetrate to varying depths. Red light (630-780 nanometers) penetrates only to about 15 meters, while blue light (420-490 nanometers) can penetrate to as deep as about 250 meters. This is why the ocean appears blue.

Actinic bulbs peak somewhere in the 420 nm range. Any plant can use blue light, not just algae. In general, red light stimulates photosynthetic carbon fixation which is incorporated into glucose, while adding blue light causes a metabolic shift so that the fixed carbon is used to synthesize organic acids, amino acids and proteins. As long as the intensity (i.e Photon Flux Density) of the light is sufficient to fix carbon from ambient CO2 the wavelength within the spectrum is irrelevant.

To give context to the quote, that was taken from a thread where someone assumed that blue light causes algae.

The other thing I wanted to mention is that I'll be willing to bet that LFS and online shops sell more so called "ideal color" bulbs (6500K) than any other color. And, I'm willing to bet that because of Matrix programming, most plant growing pre-programmed zombi hobbyist are using 6500K bulbs (because they were told to do so by thousands of other zombies), and yet, whenever a problem thread is posted on any of The Matrix websites, the zomby usually reports that they are presently using 6500K bulbs.

Now, of course it would be totally unfair, and totally inaccurate to blame their 6500K bulbs for their abysmal failure, but my point would be that 6500K did not save their plants from descending into total oblivion. From that I would conclude that a hobbyist is just as likely to have plant problems and algae using 6500K bulbs as he would using any other color bulb. That alone could be used as an argument that indeed, spectrum does not matter.

It's entirely possible that spectrum has an effect in terms of pigment production, and changes in pigment production in the leaf can have an effect on the color of the leaf, so if enough testing is done you might be able to arrive at a color combination that turns certain plants to the color you find most pleasing. A more detailed response on effects in actinic lighting vs algae growth | UK Aquatic Plant Society

So my message to thousands of test kit lovers is to stop testing kits and start testing the validity of Matrix propaganda.

Cheers,
 
I'm one of those people that claim that plants aren't fussy about spectrums.

Sorry, I can't prove it through experimental data, but I can say I've probably tried over 50 types of lighting over the years with varying spectrums and can't say one is better than the other. This is why my lighting choice is now purely based on aesthetics (colour rendition as well as the unit design) and cost (initial purchase and running cost).

It wouldn't surprise me if plants readily adapt the whatever spectrum is present. I think most plants we grow are aquatic weeds that are very opportunistic and able to utilise what's available. This principle also applies to nutrient levels, as we know.


They do. The Colour-Plus tile is now marketed under the GroBeam range because TMC realise it grows plants very well too, as does the marine 1500XG tile (9000K).

Thats interesting. So (with no expense spared) something like the Ecotech Radion unit, which from what I read you can change the colour ad nauseum) would be ideal for someone who cares more about lighting appearance ? I have to admit to liking the idea of having different colours, not only to make the plants look their best, but sometimes to make the fish look their best too... a bit like butchers who used to use redder lights to make their meat look fresher, LOL.
 
Thats interesting. So (with no expense spared) something like the Ecotech Radion unit, which from what I read you can change the colour ad nauseum) would be ideal for someone who cares more about lighting appearance ? I have to admit to liking the idea of having different colours, not only to make the plants look their best, but sometimes to make the fish look their best too... a bit like butchers who used to use redder lights to make their meat look fresher, LOL.
Exactly, but... I've used the Radion and found the glitter lines too distracting due to the intense point source effect. It's marine-bias with more blue/royal blue LEDs too which most planted aquascapers wouldn't use so much.
 
Exactly, but... I've used the Radion and found the glitter lines too distracting due to the intense point source effect. It's marine-bias with more blue/royal blue LEDs too which most planted aquascapers wouldn't use so much.

So which do you think is the most flexible and aesthetically pleasing that provide the advanced functions of LED controllers ? If only TMC would make their colourplus so that the colours could be individually controlled, it would be much better accepted, especially as its at quite a good price point as it currently stands. I saw one sell second hand for £50 on ebay a couple of weeks back. I very nearly bought it myself but was not sure if it would look nice in the tank.
 
You can answer this question yourself by simply using a specific color bulb on newly bought plants and record their growth with images, say for 8 weeks. Then repeat using a different color bulb. You can even go as far as to weigh the plants at the beginning and at the end of the test period to record the mass increase. Pick an easy plant, and purchase each batch from the same vendor to eliminate effects of inconsistent quality. Then repeat using a different plant. Note the results.

I think that this has been done here...http://www.apms.org/japm/vol15/v15p29.pdf ...

...Effects of Light Quality on Growth and Chlorophyll Composition in Hydrilla (T.K. Van et al)

It perhaps shows things in a different lighto_O
 
I'm also in the same camp as George. I haven't got the means to stringent scientific testing, however anecdotal evidence in this hobby goes along way (as long you know what you're doing). I have used different spectrum bulbs and there hasn't really been a different in plant growth or formations in the leaves. Again, aquatic plants are opportunistic weeds, that have the ability to adapt to different situations. It's survival of the fittest.
 
I'm also in the same camp as George. I haven't got the means to stringent scientific testing, however anecdotal evidence in this hobby goes along way (as long you know what you're doing). I have used different spectrum bulbs and there hasn't really been a different in plant growth or formations in the leaves. Again, aquatic plants are opportunistic weeds, that have the ability to adapt to different situations. It's survival of the fittest.

What do you make of the above paper?
 
What did you make of the above paper?

I spend pretty much zero time worrying about this sort of thing (I neglect my plants and they still grow faster than I would like), but the paper isn't terribly conclusive. Some of the spectral results sound interesting but it only looks at one plant species for 2 weeks, with very small Ns and only the red light effect on branching looks particularly significant; there's no effect on fresh weight and again only the red light (which is a fairly extreme example in hobby terms) really shows much effect on anything else.

In so much as I'd read anything into it, it seems to largely support what Clive said -

You have in fact, NOT been reading that spectrum doesn't matter, or that there are no effects of spectrum. What you've reading is that spectrum has negligible effects on plant growth rate and overall health

I will admit that I'm pretty crap when it comes plant biology though; generally I'm happy for the like of Clive and Darrel to do this sort of thinking for me (Matrix 2.0?!).
 
It would be interesting to get some backgrounds on the authors. A lot of these papers also seem to be quite old, I know that doesn't change the way plants photosynthesise, but advances in research techniques do improve. That said, it is an interesting read, but we could do with another up to date piece of evidence.
 
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