# Aqueon T8 PAR test Colormax vs Full Spectrum



## bigd603 (May 10, 2011)

Great info Matt!


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## Raymond S. (Dec 29, 2012)

Here is an interesting question for you...
The red part of LED fixtures such as the Planted+ is said not to register on PAR
meters. The Colormax is a red bulb. Can you see where this is going ?
Is it safe to say that the same red spectrum which in not being recognized in the LED bulbs(I believe mostly the 660nm ones) is at least partially in the colormax and also not being recognized in it ? Seems a logical question.


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## BigJay180 (Jul 20, 2014)

I'd want to see a water test at different depths. Red light doesn't penetrate water well, where blue does. I suspect that at 18-24 inches, color max par is effectively zero.


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## mattinmd (Aug 16, 2014)

Raymond S. said:


> Here is an interesting question for you...
> The red part of LED fixtures such as the Planted+ is said not to register on PAR
> meters. The Colormax is a red bulb. Can you see where this is going ?
> Is it safe to say that the same red spectrum which in not being recognized in the LED bulbs(I believe mostly the 660nm ones) is at least partially in the colormax and also not being recognized in it ? Seems a logical question.



So, the Apogee isn't very responsive to red light over 650nm... It's the blue line here: 









The colormax has *some* significant output over 650, but the top 3 spikes are all between 425 and 625nm... 










I don't think that lack of far-red sensitivity in apogee meters explains any past rumors..

That said, the Hoppy 2105 meter I use is somewhat more sensitive to far red, although has some weird response patterns of its own:










Bump:


BigJay180 said:


> I'd want to see a water test at different depths. Red light doesn't penetrate water well, where blue does. I suspect that at 18-24 inches, color max par is effectively zero.


Um.. I doubt that...

1) the colormax has its strongest spike in the purple-blue spectrum, 435nm Hg emissions, not the red. It also has a lot of broad-band emission in the purple/blue/green spectrum. To consider this bulb to be "all red" is deeply misconceived.

2) red doesn't penetrate at depths around 10 meters... If your tank is 30 feet deep, by all means you can consider reds to be 100% attenuated.

660nm is 68% absorbed at 24"
http://www.bmlcustom.com/custom-report-details?partNo=PS1290S201TTTTTTTTTTTTTTT

615nm orange-red is 58% absorbed at 24"
http://www.bmlcustom.com/custom-report-details?partNo=PS1290S201RRRRRRRRRRRRRRR

Based on those facts, I would find it very hard to believe that the colormax is going to always be zero at 24"... 

Sure, a single T8 in a cruddy white plastic fixture like I used might only register at a few PAR or so at those depths.. but a white spectrum T8 doesn't really register very high at those depths either, coming in at something like 10 PAR.

I've got 18" or so on my 36 gallon, I can try it out sometime.. but you're going to be comparing dim and dimmer at that depth with a single t8...


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## Tron (Jul 18, 2015)

^ +1

Sent from my USCC-E6762 using Tapatalk


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## BigJay180 (Jul 20, 2014)

mattinmd said:


> [snip out 10 paragraphs of BLAAAAAAH YOU'RE WRONG!! BLAAAAAH] single T8 in a cruddy white plastic fixture like I used might only register at a few PAR or so at those depths..


DING DING! Yes it's not "zero", but a few par at 24 inches isn't very useful either. It's only going to grow one thing. Algae.

*Here's a more useful question:*
Do you have the spectrum handy for their "FloraMax Planted" bulb? Would this be a better choice, than say, any generic full spectrum T8 bulb from Home depot? I'm asking because I run a single 48 inch Aqueon FloraMax planted in front of my 6X36 39 watt T5HO for that little extra light up front for my crypts, they seem to be okay with it. But... they're crypts and not very picky.


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## mattinmd (Aug 16, 2014)

BigJay180 said:


> DING DING! Yes it's not "zero", but a few par at 24 inches isn't very useful either. It's only going to grow one thing. Algae.


Well, that's one T8 bulb in a crappy plastic fixture... 

My point is that it's not the colormax that is the "big factor" causing the PAR to be uselessly low.. it's the choice of fixture and single-bulb T8 that's the problem..

I don't care what type of T8 bulb you use, a single T8 in crappy white plastic fixture won't grow anything at 24"... 6500k, colormax, Floramax.. it's all going to be too low.

If you're getting 50 PAR out of your full-spectrum setup, you'll get less, but not trivially less, out of a colormax.




BigJay180 said:


> *Here's a more useful question:*
> Do you have the spectrum handy for their "FloraMax Planted" bulb? Would this be a better choice, than say, any generic full spectrum T8 bulb from Home depot? I'm asking because I run a single 48 inch Aqueon FloraMax planted in front of my 6X36 39 watt T5HO for that little extra light up front for my crypts, they seem to be okay with it. But... they're crypts and not very picky.


The floramax is a similar bulb spectrum-wise, but with the red stacked more at 650nm, and not as wide-band:










Side by side:









And the full-spectrum:










Of course, none of this speaks to efficiencies.. as my test shows, the colormax seems to generate less light per watt than the full spectrum.


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## BigJay180 (Jul 20, 2014)

mattinmd said:


> Of course, none of this speaks to efficiencies.. as my test shows, the colormax seems to generate less light per watt than the full spectrum.


Yeah, in my case I have just one bulb in a bad reflector. My T5's are in individually mirrored Catalina reflectors, and do most of the work.

I'm just using it as a supplement because my T5 coverage isn't quite perfect at the very front of the tank where my favorite crypt plants are. The efficiency question is interesting though, is it better to have more lumens in a broad spectrum, or fewer lumens with spikes in the photosynthetic active ranges?


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## mattinmd (Aug 16, 2014)

BigJay180 said:


> Yeah, in my case I have just one bulb in a bad reflector. My T5's are in individually mirrored Catalina reflectors, and do most of the work.
> 
> I'm just using it as a supplement because my T5 coverage isn't quite perfect at the very front of the tank where my favorite crypt plants are. The efficiency question is interesting though, is it better to have more lumens in a broad spectrum, or fewer lumens with spikes in the photosynthetic active ranges?


It doesn't matter really...

100 photons all the same color, vs 100 photons each a different color is really all the same, baring a bit of difference in the plant response to the specific colors chosen.

If you look at the plant response curve (green line in the apogee chart) you'll see that some colors are slightly better than others, so this does have some impact.. 

That said, if you look at the response curve, the lowest point within visible ranges is still 65% responsive.. it's not like there's massive holes in plant utilization of light..


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## Oso Polar (Apr 22, 2015)

Hmm, I don't think it doesn't matter, it really does. When talking about lumens it is not only plants response curve that is taken into account (https://en.wikipedia.org/wiki/Photo...esis_yield_photon_flux_spectral_weighting.svg) but also human eye response curve: https://en.wikipedia.org/wiki/Luminosity_function

In other words, light that mostly produces light around 555 nm will have much more lumens compared to light that produces most of the output around 650 nm. And by "much more" I mean like easily >10 times more - just compare two curves. That's actually the main reason we use PAR and not lumens.


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## Oso Polar (Apr 22, 2015)

That being said, I have no idea how to use this info in practice without PAR meter. E.g. you have one bulb with 200 lumens and another with 1000 lumens. I can tell that first will look dim for me compared to the second but I'll not be able to give a definite answer which one will be better for plant growth even having the picture of the light spectrum of each bulb in front: this will require to apply both curves on top of the spectrum curve. There is no way somebody can do this in their head.


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## mattinmd (Aug 16, 2014)

Oso Polar said:


> Hmm, I don't think it doesn't matter, it really does. When talking about lumens it is not only plants response curve that is taken into account


Who said anything about lumens?.. I said photons... PAR is inherently photon-count based...


edit: Scratch that.. I see that BigJay said lumens.. I missed that originally.

Bigjay - Oso's pretty much right here.. Lumens are pretty much a completely useless measure of light when it comes to photosynthesis.. by saying lumens you're implying a specific spectral weighting based on human eye response..


If you take it back to pure photon counts, or even energy levels then my answer works...

Those spectrum graphs are relative energy distributions, not lumen oriented at all.


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## BigJay180 (Jul 20, 2014)

Thanks matinmd and Oso, this is all good stuff to know.


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## mattinmd (Aug 16, 2014)

So, for what it's worth, I took a little time and played with it in-water..


This sits lower on my tank than my finnex lights do, actually sitting down inside the rim and having no legs... Thus I got 18" from light to substrate, 17.5" of which is water. The tank was also somewhat cluttered with plants, so I wouldn't say this measurement is a good measure of absolute PAR, which would likely be higher if the tank wasn't overgrown, but I tried my best.. it should be close.

Regardless, it should be a good relative comparison through a reasonable amount of water.

18" in-water, 10 minute warm-up:
Full spectrum - 16 PAR
Colormax - 8 PAR

So we're at 50% instead of 60% less...


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## burr740 (Feb 19, 2014)

Interesting thread, thanks for doing this. I have a homemade light box over a 20L using 2 T8s, with pretty good individual reflectors which I fabbed out of aluminum flashing. Im in the market for one new reddish bulb, so this is good info to have. 

Currently have one Hagen life-glo that's putting out low 30s par @ 12", the other bulb is a wal-mart "plant bulb." It's a nice red color, and started out great in the upper 20s, but now after 2 months it's barely doing 15.

I was actually considering a colormax but after seeing these results I may go a different route, even if it means another full spectrum. My aim on this tank is at least 50-60.


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