# Best T5 Bulb Combo



## whitetiprs13 (Aug 12, 2011)

What combination of T5 HO bulbs work the best for growth and color. 
I currently have a 10K and a 6500k


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## EvilLost (Jan 10, 2011)

6500K for non-aquatics imho

if you are really heavy on foliage you can maybe raise it a little more, but I would not use 10K for anything but aquatics (MAYBE for emersed / riparium setups like Hydrophyte has going...he can comment better on those)


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## WeeNe858 (Sep 13, 2010)

65k has the proper spectrum for plant growth and the 10k has the intensity to make colors pop. The current combo you have won't hurt anything but if you want more usable lighting, try swapping the 10k for another 65k when it burns out. (no point tossing a perfectly usable light.)

Another option is the 5k lighting for more plant growth but its less common.


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## bratyboy2 (Jan 29, 2010)

Actually the 5k bulb you can get I can't remeber the name of the company but grim has the light fixture over his peninsula tank.


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## WeeNe858 (Sep 13, 2010)

I was looking around and ZooMed has t5 HO in 5k.


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## jibfest (Dec 1, 2010)

6500/6700K have best plant growth and will really do well color up broms. 2700/3000K is a good choice in addition to the 6700K to promote flowering in orchids etc.


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## EvilLost (Jan 10, 2011)

WeeNe858 said:


> 65k has the proper spectrum for plant growth and the 10k has the intensity to make colors pop. The current combo you have won't hurt anything but if you want more usable lighting, try swapping the 10k for another 65k when it burns out. (no point tossing a perfectly usable light.)
> 
> Another option is the 5k lighting for more plant growth but its less common.


this is not correct.


the "color temperature" is a representation of the relative spectral distribution of the light. it has NOTHING to do with the intensity of light output (that depends on the wattage of the bulb, usually).

for aquatic setups blue wavelenghts are much more necessary b/c red wavelenghts don't penetrate the water layers. 

for non-aquatic plants however, generation of both chlorophyll a and b has been shown to be strongly benefitted by red light. In fact, look up any "grow light" and you will find they are heavy in the red spectrum (which would make their color temperature much lower). 

a 10K bulb will make your colors pop in a coral or reef setup, but for terrestrial plants it will do exactly the opposite...


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## whitetiprs13 (Aug 12, 2011)

Thanks I will try swapping out the 10K for another 6500k when it comes time to change the bulbs.


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## carbonetc (Oct 13, 2008)

There are two wavelengths of light most useful to plants: ~460nm and ~660nm.

The usual 6500K (daylight) tube is great for covering 460nm. A tube around 4400K will give you 660nm -- these have a pinkish color to them and are usually sold as lights specifically for plants. 

The light these two lamps produce together is very pleasing to my eye. To me 6500K looks too cold and sterile, and pink is, well, pink.

I'm hoping to get more experience with 10,000K (around 300nm). It doesn't seem like it would be that useful for plant growth, but it's pretty popular. I've been trying to figure out why.


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## EvilLost (Jan 10, 2011)

carbonetc said:


> There are two wavelengths of light most useful to plants: ~460nm and ~660nm.
> 
> The usual 6500K (daylight) tube is great for covering 460nm. A tube around 4400K will give you 660nm -- these have a pinkish color to them and are usually sold as lights specifically for plants.
> 
> ...


Color temperature DOES NOT directly correlate to wavelength. 

However, color temperature is only a reference to an aggregate combination of the light emitted. It does NOT imply any particular wavelength is emitted. In other words, you can have 10 different 6500K bulbs that all output entirely different spectra.

A lower color temperature does imply a more "red" light and a higher temperature a more "blue" light; this is true, but it does not mean the particular wavelengths desired are present (or in appropriate amounts) or that other wavelengths are not present.

EDIT: blues are around 400nm btw; 300nm is UVB spectra

EDIT2: to answer your question regarding why 10,000K bulbs are popular, it is because AQUATIC setups (corals and underwater plants) do not make the same use of the red wavelengths as non-aquatic plants. I believe this has to do with the penetration of light into the water (ie the blues make it deep into the water, and the reds dont). Therefore they have evolved to thrive on blue-heavy light and so higher color temps benefit these setups better.


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## WeeNe858 (Sep 13, 2010)

I think were getting too technically with the question here.. lol. 

Go for a 65K or a 5K, whichever you fall upon first.


*65k is actually the same recommended lighting for freshwater aquatic plants. The 10K gives part of the intensive lighting needed in the reef hobby. This is from experience. But of course, I use these terms loosely.


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## ZookeeperDoug (Jun 5, 2011)

Honestly what we need is for manufacturers in the hobby to begin producing lamps of various kinds that produce the proper wavelengths and intensities of light for live terrestrial plant growth, much as has happened with the reef aquarium hobby. Fortunately most 6500k bulbs, get the job done, but lamps specifically designed for our purposes could do the job even better. 

A perfect example is the ADA 8000k bulbs, far above what one would consider the best for live plant growth, but they are excellent for their intended purpose, growing aquarium plants.

Keep in mind to, crazy plant growth is not always desirable. We're often trying to keep our plants small in vivs, providing intense lighting can cause them to grow too quickly, become leggy, need to be trimmed or pruned often, etc.


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## EvilLost (Jan 10, 2011)

@ZookeeperDoug: what kind of bulb would you suggest?

I don't think there is "one" bulb for manufacturers to make that would be any significant improvement over current bulbs. Most 6500K bulbs have a pretty good balance of reds:blues and are pretty ideal for our setups.

If you really want more colors/flowers, then supplement your light with a slightly more red-heavy light as others have suggested. Personally, I do not like the visual effect this has so I stick to 6500K across the board.

And as you said, crazy plant growth isn't necessarily a good thing....


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## Arpeggio (Jan 15, 2011)

GE starcoat 6500k are the perfect T5ho for freshwater and plants for me, IMHO. Bright and cheap!


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