# CFL Bulb :: GE Daylight vs. Exo-Terra Repti Glo 2.0



## froggysan (Sep 14, 2008)

Alrighty.... I'm working on a rather unique project and have officially decided that compact flourescent bulbs are going to fit the bill perfectly. Don't ask me to go into detail on the project... it's way to complex for this thread.

Just here for the bulb show down.

GE Energy Smart Daylight Bulb
Color temperature of 6500K
1600 lumens
CRI ???
26 watts
Cost ~$5.00CDN

Exo-Terra Repti Glo 2.0
Color temperature of 6700K
Lumens ???
CRI of 98
26 watts
Cost ~$20.00CDN


Color temperature is the measurement of what hue a light gives off. The lower the K, the warmer the light is, the higher the more like pure white. A light in the 6500K is said to be much like daylight overcast. We want 6500K for reptile and frog enclosures.

CRI is the ability of a light source to render the color of objects accurately as compared to the sun. 100 being the sun, 0 being pitch black. How important is this? Is this related to the color temperature? Like if a bulb has a temp of 6700K can one say it has a CRI of 98?

And lastly lumens or lux is the amount of light generated by a light source. The more lumens... the brighter the light is, the more area it'll light up, right? Do all 26 watt CFL's produce around the same lumens of 1500?



If it were just one, two, maybe three of these I needed for my project I would just dish out the extra cash and get the Exo-Terra... But in my case I'm going to need around 10 of them I think.

Do you think these GE 6500K daylight's will work?


Let the banana throwing begin!


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## stemcellular (Jun 26, 2008)

They are all I use on my tanks (26W, 20W and 15W) and (as you can see by searching my past posts) I get amazing growth and healthy frogs. G'luck!


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## Philsuma (Jul 18, 2006)

You have my interest!


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## froggysan (Sep 14, 2008)

After a lot of digging I found the CRI of the GE Daylight bulb... it's reported to be 82.


All that's left is to figure out the lumens of the Exo-Terra bulb...


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## carbonetc (Oct 13, 2008)

I highly doubt you'll see any difference in growth. I always feel ripped off when I buy lighting products specifically for fish or reptiles. You know the price is getting seriously inflated.


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## frogparty (Dec 27, 2007)

I have been using the exo terra full spectrum bulbs and my orchids and broms are doing awesome! haven't tried the ge daylight bulbs yet, just found out about them, but other people here use them with great success!


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## Dancing frogs (Feb 20, 2004)

The CRI is a tricky measurement...higher number obviously better.

The tricky part is that it refers to how acurate a source is at the rated wavelength.
So in theory, if you had a 20,000k bulb that was rated at 100 CRI, it wouldn't render much color other than blues and violets but would do so very well...a red frog wouldn't look very red under that light. (if memory serves me correctly anyway)

When I shop for bulbs, I look for something 5,000 to 7000K...with as high a CRI as I can get. 
You can also mix bulbs in dual-bulb fixtures to get a decent effect...
For example, I bought a cheap 2 foot shoplight that only takes t-8's...it came with 3000k (warm)bulbs and couldn't find a store (without ordering) that sold daylight 24" t-8s, so instead I replaced just one of the bulbs with a 10,000k bulb from a fish shop, and it actually blends to look pretty good.


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## froggysan (Sep 14, 2008)

Actually I'll be doing the same... sort of.

The fixture/hood/canopy... whatever you want to call it... is actually going to have 12 sockets in total. 4 of them are going to be occupied by 4 different CFL bulb types that I've selected to address specific UV/heat requirements in different sections of the the whole setup. 

The remaining 8 were going to be filled with Exo-Terra Repti Glo 2.0's at $20CDN a pop for visual light purposes. But with the GE Daylight CFLs providing everything the ET bulbs do (except for about a 16% lower CRI, which will likely be remedied when used with the other specialty bulbs I have planned) and costing only $5 each... I think I'll hang onto the $120+ in savings and buy myself something frilly!


Oh... and for those wondering... this is not for a PDF tank at the moment... and the setup won't be housing any live plants either. It's complicated... Don't ask.


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## jehitch (Jun 8, 2007)

froggysan said:


> ... I think I'll hang onto the $120+ in savings and buy myself something frilly!


Definitely skip the Exos. We sell them in our store, but use regular 6500Ks in store fixtures for frogs and plants. You can probably even save more if you look for multi-paks of bulbs. A local store is advertising three packs of 26 watt 6500Ks for $4.98 U.S.

Jim


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## Nick_ (Mar 24, 2008)

Just a little word form the industry side of reptiles and other critters....all light bulbs marketed and sold through 'companies' like zoomed, t-rex, and the others, are adapted from either GE or other household bulbs. There is not one, and I mean one, bulb that has been built from the ground up by rd of any animal based company rather than salvaging ques from already exiosting bulbs and lamps. Even the patented bulbs like "Power Sun", "Sun Seeker", and the 5-10.0 series and others, are simply bought out and repacked. There are some slight changes that RD make on them like printing and perhaps ordering specific filaments from manufacturers, but other than that they are simple adaptations from bulbs you can find online or at home improvement stores. This is persoanlly what I do when looking for specific lamps for either myself or a customer, I goto lowes or homedepot and pull the specs of the lamp up on google with my phone and directly compare them with available bulbs in the store.


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## Philsuma (Jul 18, 2006)

Good Post Nicholas!

Thanks.


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## froggysan (Sep 14, 2008)

Nicholas,

This is something I have long since suspected. It's very similar in the LCD Monitor and TV industry. In fact only a few companies -- Sharp, NEC, and Samsung -- actually manufacture the LCD pannels. The rest of the companies simply buy their panels and then put them in their own casing and products.


What I'm interested in knowing is how companies like Zoo Med and Exo-Terra get their flourescent bulbs to produce UVB. For example, the Exo-Terra Repti Glo 5.0 and 10.0.... 

What exactly is done to the bulb that causes them to output UVB?


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## Tony (Oct 13, 2008)

froggysan said:


> What I'm interested in knowing is how companies like Zoo Med and Exo-Terra get their flourescent bulbs to produce UVB. For example, the Exo-Terra Repti Glo 5.0 and 10.0....
> 
> What exactly is done to the bulb that causes them to output UVB?


From what I understand the combination of phosphors inside the bulb control what spectrum of light is produced. I'm curious to know what the home depot equivalent of a 5.0 uvb reptile bulb is. That bit of knowledge could be a huge money saver.


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## jehitch (Jun 8, 2007)

froggysan said:


> What exactly is done to the bulb that causes them to output UVB?


My understanding is that all fluorescent light sources produce UV radiation; but it's what is done to STOP the output of UV in home-use bulbs that makes them different.


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## froggysan (Sep 14, 2008)

I did a little reading up on fluorescent lighting to understand how exactly it works. Granted most of the science is way over my head, what I did absorb was that inside a fluorescent lamp is a vacuum and a small amount of mercury. When an electric charge is introduced, the mercury emits light in the UV spectrum. The bulb itself is coated with a phosphor that absorbs the UV light and through a chemical reaction then produces a visible light.

You folks are right... The coating is different on the Zoo Med and Exo-Terra 5.0 and 10.0 bulbs so that they allow a bit of the UV to pass through.


I doubt there is Home Depot equivalent since outside the pet market and health market there is little need for a bulb that emits small amounts of UVB.


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## Nick_ (Mar 24, 2008)

jehitch said:


> My understanding is that all fluorescent light sources produce UV radiation; but it's what is done to STOP the output of UV in home-use bulbs that makes them different.


That is spot on, and is infact the main difference between a regular phillips 40 watt high color temperature lamp and a reptiglo 5.0.

There are some very neat little metal halides and sodium lamps that would look and work like a charm in viv's. Also the fixtures available at home improvement stores are killer, a bit of wiring can give you a very nice one off lighting system for the price of an overhyped lamp alone.


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## Nick_ (Mar 24, 2008)

froggysan said:


> I did a little reading up on fluorescent lighting to understand how exactly it works. Granted most of the science is way over my head, what I did absorb was that inside a fluorescent lamp is a vacuum and a small amount of mercury. When an electric charge is introduced, the mercury emits light in the UV spectrum. The bulb itself is coated with a phosphor that absorbs the UV light and through a chemical reaction then produces a visible light.
> 
> You folks are right... The coating is different on the Zoo Med and Exo-Terra 5.0 and 10.0 bulbs so that they allow a bit of the UV to pass through.
> 
> ...


There is a plethera of lamps from home depot that sqaunder any attempt by any of the reptile/pet moguls at making a marketable bulb. Luckily for them the majority of thier consumers don't experiment with lighting too much. Lower wattage lamps for outdoor use generally donot have any or as much uv protectant as interior lamps do. A UV meter is relativley cheap and a good investment for hobbyists who build alot of vivs or simply aquire new ones on a regular basis, as lighting is one of the most expensive aspects of keeping any critters.


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## Catfur (Oct 5, 2004)

There is, sadly, some really bad information floating around in this thread (in addition to some valid information).

First off some definitions (for clarification).

Color Temperature: Color temperature is either the temperature of a black body radiator (such as an incandescent or halogen light bulb, or the sun), or the temperature of the black body radiator which correlates most closely to the spectral output of a light source (such as a fluorescent, or gas discharge bulb). 

Color Rendering Index (CRI): CRI is, for a non-blackbody light source, defined as the "Effect of an illuminant on the color appearance of objects by conscious or subconscious comparison with their color appearance under a reference illuminant" (from CIE 17.4, via Wikipedia).

Now some facts.

UV radiation is light with a wavelength from 400nm to 10nm. 

UVA (400-320nm) and UVB (320-280) radiation are present in natural sunlight, UVC (280-100) radiation is filtered out by the atomosphere (ozone layer).

UVB radiation is required for Vitamin D synthesis, wavelengths of 295-300nm are optimal. UVA & UVC do not generate Vitamin D. Special phosphors are used by manufacturers of UVB lights to generate these wavelengths via florescence, the UV light produced by low pressure mercury vapor is ~240nm (UVC).

Fluorescent light bulbs do not include any special material to prevent transmission of UV, the ordinary glass they are made out of does not transmit UV in any appreciable amount. UVB bulbs are made from special glasses that transmit UVB but not UVC (germicidal bulbs are made from glasses that transmit UVC and do not contain any phosphors). You will not find any ordinary light bulbs at BigBox Mart that emit useful values of UVB.

These special UVB emitting phosphors, and UVB transmitting glasses, as well as the lower production quantities of the bulbs, are the reason that UVB bulbs (such as the Exo-Terra Repti-Glo) are more expensive than similar, ordinary fluorescent bulbs. Some UVB bulbs are better than others, yes. The Chicago Herpetological Society published a very good article on UVB bulbs a couple of years ago (3 or 4?), you can probably find that if you want to find out more about UVB bulbs for herps.


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## Philsuma (Jul 18, 2006)

Bump for update on double secret lighting project.....


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