T8 advice

Sara_Notfors

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26 Jan 2020
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Hi all,

I'm looking at lighting for my Fluval Roma 200 that will be low tech but with lots of plants. I bought it second hand and it came with one T8 30W Sun-Glo tube, what should I buy to complement it? Further down the line I'm going to invest in LEDs, but will go for this option for now.

TIA,

Sara
 

oreo57

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Sun-glo Is An Excellent Aquarium Bulb For Emitting A Warm White L(ight)
How warm does it look and what do you want it to look like?
Warm tubes are rich in red and short in blue.. A compliment would be the opposite..
https://www.petswarehouse.com/hagen-glo-30w-aqua-glo-fluorescent-bulb-t8-36in-a1585/

Listed as 18000K so very bluish.but the bulb will be a personal choice..

your current bulb is 4200K I believe..
The 2 combined may be a bit cool for some.. Rough average would be a 11000K
 

rubadudbdub

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This is my Rio 125 on 2 T8s. Theres a fairly thick mat of floating plants so it looks darker and greener tinged than it would without the floating plants. They're daylight colour ~6500k cheap tubes from lampspec.co.uk. They're called 865 tubes. http://www.lampspecs.co.uk/Light-Bulbs-Tubes/T8-1-Inch-Diameter

I have no problem growing crypts, limnophila, anubias, vallis nana, sagitarria. Easy stuff. Java moss dies back if the floating plants get too much cover.

I've tried grolux (too pink) and bluer tubes, 880 on lampspec. The 865 (6500k) are the ones I've stuck with. I use them til they fail. But they go from 100% to 80% after 12 months. I'm not growing anything demanding enough for it to be an issue.

There's a better write up on James' planted tank website, where I pinched the suggestion from :)
 

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Simon Cole

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Warm tubes are rich in red and short in blue..
Mythbusters please. The chroma makes it blue or red. The kelvin is more like where this light would be found in the world if you used sunlight.

Personally I like 5000 K. Get lots of tubes and mix them around. I would probably start with a pinkish tube to compliment it. I like to feel I'm on holiday somewhere warm and tropical, and the red makes things pop.
 

oreo57

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Hagen sun glow spectrum:

Hagen aqua glow..

http://inf.ovh/aquarium/aquarium-lighting-market

I suppose what I said was a bit of a stretch w/ the CCT of tubes..
Off the cuff I wasn't expecting soo much red phosphors in a 18000"K" tube.
See Power Glow (also listed as 18000K).

Must be more of my focus on LED's.. ;)
More "typical" spectrum:
wavepointsunwave.JPG




There is an infinite amount of "colors" one can mix to get the same average K temp.. (more correctly CCT)

Granted these are relative not absolute values.. but useable.
Of course the bottom line is ones own eyes to add enjoyment to function..

o/p wanted to compliment the sun glow tube.. the aqua glow would still be a worthwhile try..
 

oreo57

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OK, had to do it..
Hagen sun + aqua.
Aqua has a really healthy, and COMPLETELY unexpected, 660nm output.
When importing the spectrum it didn't register any "k" value.
It would need a healthy dose of green to get it to 18000"k"
One of my issues w/ some lights.. Have no idea where they get their k ratings from..
Sun glow was ok..Registered as 5000"k"
A couple of caveats.. treated them as equal lumen output and beam angle of 135 (not important here really)

Combined spectrums.
Wonder if the math and reality are similar..

hagencombo.JPG


 
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Simon Cole

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Spectrum distribution charts do not really look anything like the ones above.
The spikes are sharper, not round, smooth or squared.
Those were made using an excel chart plotter based upon assumed values. Here are some typical peaks:
Hg Mercury spikes: 365, 405, 436, 546, and 579 nm
BaMg2Al16O27:Eu2+: 452 nm peak with ½ height bandwidth of 51 nm, contribution 400 to 510 nm.
CeMgAl11O19:Tb3+: Main peak at 544 nm, minor peaks at 488, 577, 579, 584, 617, 621 nm
Y2O3:Eu3+: Main peak at 611 nm, minor peaks at 589, 593, 600, 650, 663, 688, 694, 707, 709, and 713 nm
Argon: 760, and 809 nm.

The person that put those chart together just used excel to smooth the peaks - and went into MS paint to take the tops off - leaving them square. There is no law of averages when photons have specific energies. It's even more funny when you spot the ones that have no 100% peak. That is theoretically impossible.

Yes I'm sure Hagen have a T8 tube making factory. That is how they got these "completely unexpected" values. Or perhaps it was just industry standard tubes re-branded. And then the arts and marketing team had a go.
 

oreo57

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Spectrum distribution charts do not really look anything like the ones above.
The spikes are sharper, not round, smooth or squared.
Certainly agree that the Hagen charts are err.. ODD but the overall spectrum is quite indicative of the photographed "look" of the tube..
As to the short of 100% yea sort of a glitch w/ little practical implications.

Another "type" would use photon counts.

https://premiumaquatics.com/products/reef-brite-54-watt-t5-ho-5050.html
10,000"K"
Does show the mercury spikes vs phosphor smear better,,
Using what one is provided isn't worse than eyeball guessing.. ;)
As to the 100% chart thing.. doesn't actually change the relative proportions of wavelengths and would be as easy to mathematically correct as it was created.

As a side note.. Almost every Reef Centric Metal Halide listed as "20000K" specs nowhere near that.
Should just be called blue bulbs.
Then there is the use of the term "actinic"..

[*]
relating to or denoting light able to cause photochemical reactions, as in photography, through having a significant short wavelength or ultraviolet component.
There are plenty of anomalies that are distracting but one can work around them.


rough spectrum chart done using the osram spectrum software. I only mapped the peaks and dips as resolution points to get a really rough estimate.
Bridgelux Thrive 6500K x2 + 5000K x1
Note: not my "data"..
Yea plenty of areas to manipulate data..

Tools used:
http://spectra.1023world.net/#save
https://apps.automeris.io/wpd/
https://notepad-plus-plus.org/

Example of data import (goes to 100):
Viosis spectrum import
 
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Simon Cole

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I quite like the ones that look a bit like a colour map. They have R,G,B in each of the 3 corners and plot a distribution over the range. Not ideal, but better than Hagen's current illustrations. Great info above, thank you. I am still a devoted T5 user. I just love the mixes and vibrancy you can get with the bulbs. The colours I choose light up the entire room in vibrant colour and what I like is typically 4 tubes (pink, very warm, cool and cool). But the intensity of these new HO tubes is a major downside because it places a strain on the entire aquarium. Two T8s sounds like a nice way to go.
 

Simon Cole

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You can probably guess what I am going to say about those spectrums too. The RGBV component/phosphors can only emit light at their given energies. The idea that it "emits full-spectrum light close to the natural sunlight" is fundamentally flawed for exactly that reason. Their website even refers to this as "blending" so what they are saying is entirely contradictory. There are actually massive wavelength gaps between each wave band. And it is also true that these bands are far steeper and more narrow that anything close to full spectrum. Plants are still quite happy and the light can look white, but we need be honest about the fact that full spectrum is just a sales term. Compiling and broadening these narrow-band peaks into one chart, and then smoothing the average is totally misleading. Really this myth was busted a long time ago. The term "close" to sunlight is at best a comparative analogy and at worst a subjective opinion. I would like to see the "proprietary information" you base your opinion upon.
 

oreo57

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Really this myth was busted a long time ago. The term "close" to sunlight is at best a comparative analogy and at worst a subjective opinion. I would like to see the "proprietary information" you base your opinion upon.
I'd like to see some RAW data from you actually..
On that note ALL common light types rely on some "smoothing"... though I think you are WAY over-estimating the "errors"..
1593056862454.png


https://www.researchgate.net/figure...yed-in-our-VLC-system-together_fig1_275673962
Or you want to "smooth" the600nm phosphor area .. go for it.
smooth.JPG


Solis 1c, 2c and 3c data (white led) nm by nm and find the "holes"..
Thorlabs white led nm by nm
Data normalized to "1"..

https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=8986

https://www.researchgate.net/figure...n-driven-with-dc-currents-from_fig1_234875131
 
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Simon Cole

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I'd like to see some RAW data from you actually..
On that note ALL common light types rely on some "smoothing"... though I think you are WAY over-estimating the "errors"..
Firstly, I do not have any rights to their "proprietary information". Neither could I legally publish this data as you suggest.

Secondly, there is no need for "smoothing".

Thirdly, "smoothing" misleads customers.

Fourthly, I did not estimate how erroneous the charts were. I said that the analogy is a myth. To clarify this further, I do not see them as valid, verifiable, nor reliable.

Or you want to "smooth" the600nm phosphor area .. go for it.
Thank you for providing a variety of sources and asking whether I would like to have a go at smoothing these peaks. The answer is no I would not thank you. I think it would be quite deceptive personally.
 

oreo57

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Fourthly, I did not estimate how erroneous the charts were. I said that the analogy is a myth. To clarify this further, I do not see them as valid, verifiable, nor reliable.
To each their own..
rgbphotoncrt.JPG

Note may not be CRT phosphors..
https://books.google.com/books?id=h8ss6Z_OyvcC&pg=PR14&lpg=PR14&dq=cees+R+Rhonda+led+phosphor&source=bl&ots=5uMqpk5Zms&sig=ACfU3U1vsB57ebOyB9XSFqisczjdE43GZg&hl=en&sa=X&ved=2ahUKEwjf0-a4sp3qAhWPK80KHWtuAp8Q6AEwAHoECAsQAQ#v=onepage&q=cees R Rhonda led phosphor&f=false


There are actually massive wavelength gaps between each wave band. And it is also true that these bands are far steeper and more narrow that anything close to full spectrum.

Might help if you brought proof not just hearsay..
 
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Simon Cole

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Might help if you brought proof not just hearsay..
I didn't need to substantiate how different LED light is to sunlight. You just did that for me.

Anybody can now look at a spectrum for sunlight and make up their own mind from the information you kindly provided.

The original post was simply to recommend a suitable T8 tube. I do not think it is in anybodies interest to read all of this if they want to buy a new tube. So as far as I am concerned - it is time for me to stop posting in this thread. I am sorry that I cannot answer all of your questions here. I will certainly try and help you if you want to post your questions in the lighting section :)
 
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