Why coil bulbs are not the best

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Why coil bulbs are not the best

Postby Salai » Mon Nov 30, 2020 6:03 am

I was recently explained, why coils are not that efficient.
Before that, all I was getting was “replace the coil with linear!” and “coil is bad!”
No one explained it to me WHY there would be anything wrong with the coil, except constantly bringing up diseases. So I chose to ignore it and stick with the coil.
Then, when I was buying a new bulb (the old one had to be replaced) I asked the salesperson about it, and she kindly explained to me, that while coil UVB bulbs only cover one particular spot in the tank, the linear UVB lightbulb covers most of the surface in the tank and since beardies don’t spend all the time on the basking spot, they might not get the right amount of UVB with the coil.
After that, I decided to buy the linear light bulb, and share this with anyone who is all the same only getting straight forward instructions to replace the coil with the linear lighting and no explanations why to do it.

Here is a picture I took from the packaging of the lightbulb, to help with the explanation:
[Click image to enlarge]

I really hope that this helps people getting the further idea of why the coil is not as good as linear lighting.

Take care!
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Re: Why coil bulbs are not the best

Postby SpikeysM0m » Mon Nov 30, 2020 7:39 am

This actually makes so much sense. Thank you for sharing.
May I ask you to share what time of linear light you purchased. Our baby dragon has only been home 2 days...
Things are not easy and we feel he is very stressed. So I am getting ready to post our setup and see if we can help him get more comfortable.
Thanks again
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Re: Why coil bulbs are not the best

Postby Salai » Mon Nov 30, 2020 9:25 am

Sure thing!
I bought an Exo Terra reptile UVB 150(18 W), but the light you buy also depends on the size of you tank and the height at which the lighting will hang on.
I’ve had my boy since he was 10 days old, and he did just fine with coil too, so I wouldn’t worry much if you’ve still got the coil lamp.
But my breeder did bring it to my attention, that the coil should be no more than 30 cm(about 12 inches) from the ground of the tank in order for beardies to get the optimum amount of UVB rays.
But for the coil... I’ve been buying the Exo Terra Teptile UVB 200(25 W), the stronger one, because, as I said, they are only receiving the light from the coil on a particular spot.
I’m not really sure if the brand of the lighting helps, since I’m guessing you’re from US, and I’m from over the pond in EU, but if you head over to the local pet store, they should give you some advice on lighting too.
BUT!!! Please check the data TWICE, because there are some cases when the data given was wrong and resulted in illness or metabolic diseases.
I do not however mean to scare you.
I’m sure you’ll figure it out, like we all had to!

Good luck with your dragon!
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Re: Why coil bulbs are not the best

Postby KarrieRee » Mon Nov 30, 2020 1:40 pm

Here is some info on UVB -- I am not a fan of coils and do not recommend them at all -- too many horror stories about them and seen on this forum
Which UVB light should I use?
The best UVB light is a ReptiSun 10.0 fluorescent tube HO (Or Arcardia 12% in the UK). Compact or coil bulbs do not emit the proper amount of UVB light for a bearded dragon, and should not be used. Other brands, such as the Zilla Desert Series and ReptiGlo have been known to cause eye problems and other health issues with bearded dragons, and should be avoided. The reason that some UVB lights (Zilla, ReptiGlo, coils/compacts, ect.) are considered dangerous is because the wavelength of UVB that they emit is shorter and more intense than the wavelength of the "safe" lights (ReptiSun, Arcadia). UVB lights should be replaced every 6 months. The T5’s are a strong bulb and only need to be replaced once a year – the T 8 every 6 months--- where as the T 8 are not as strong—they need to be placed inside the tank the T 5 10.0 bulb approx 12-15 inches from basking spot – the T 8 approx 6-8 inches from basking spot—the cover needs to be off the bulb for full effect of the UVB rays--
The long tube fixtures w/ the Reptisun bulbs or Arcadias are the best in the market at this time
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Re: Why coil bulbs are not the best

Postby cliffhangerreptiles » Thu Dec 03, 2020 2:47 pm

Ultraviolet light is measured in µW/cm². I've tested several bulbs, and the general result is that bulbs with a standard base put out a significantly lower UV reading. Bulbs with a T6 or T5 base (the long tube-like ones) have a higher reading. On top of that, T5 is typically better than T6.

And, of course, the longer bulbs cover more of the enclosure.

I hope this helps!

Blake M
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Re: Why coil bulbs are not the best

Postby CooperDragon » Thu Dec 03, 2020 3:07 pm

The tests I've done on some of the bulbs agree with what you're saying. The UVB150 compact produces about the same output strength as a T8 w/reflector, but the output drops off significantly as you move to the side of the bulb. Since you want to create a zone of roughly equal temperature and roughly equal UVB intensity over the basking area that is the length of your dragon, the wider beams make sense. Especially as they reach full size, you're looking at 18-24'' diameter basking zone at least. This is more easily achieved by using a tube style bulb. Some wide angle MVBs can do this as long as they are high enough, or you could try to cluster some compacts together, although at that point the cost benefit would probably not make it worthwhile. There are more details about lighting on the advanced discussion boards.

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