I have a 25 watt Zilla mini halogen bulb (day blue) on our new lizard terrarium. It claims to have UVB, but there are no claims of UVA.

Can I assume assume UVA is included since it is a longer wavelength than UVB? Why can I not find any mini halogen bulbs that claim both UVA and UVB?

(I've also asked the manufacturer -- will post their answer as well if they reply.)

EDIT: Not sure how to adjust this question, but it has a false premise. The halogen bulb does not claim UVB!

Confirmed from manufacturer support:

The Zilla mini halogen bulbs are for basic light and heat, they do not provided any UVB/UVA. You will need either one of the tropical or desert series fluorescent bulbs that provide essential UVB/UVA.

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    Who gave you the idea that the halogen bulb will give you UV light anyway? On their site (the link you provided) they advertise it for IR light, which is exactly on the other side of the spectrum. It will only generate light and heat - plus some irrelevant residue frequencies. – virolino Jul 16 '20 at 6:58
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    @virolino That's a good question -- I'd swear I saw UVB on the bulb packaging (which is thrown away) -- and the bulb description says -- "Fits with Zilla fixtures: Halogen Mini Dome, Heat & UVB Basking, Mini Heat & UVB and more!" -- which I realize now isn't describing the bulb at all! The UVB fixtures mentioned are dual bulb fixtures.. – rrauenza Jul 16 '20 at 7:18
  • Yes, that is my understanding also :) – virolino Jul 16 '20 at 7:39
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    halogen bulbs are made of quartz glass,quartz glass let uva and uvb pass thru so yes you will get some uva and uvb light.regular glass will block parts of the uv spectrum,uvc is fully blocked by regular glass but uva and uvb will pass.allmost all light sources give of uva light en.wikipedia.org/wiki/Ultraviolet – trond hansen Jul 16 '20 at 9:01
  • @trondhansen: we did not question the materials used. We questioned the amount of UVA and UVB generated. Do you have info about this? Are they in any relevant quantities in halogen bulbs? – virolino Jul 17 '20 at 5:54

When generated artificially, UV light is generated in very narrow bands. So it is quite possible that you only get what is advertised. The generation is based on how atoms work - at the level of electrons, orbitals, energy levels...

Of course, some residues exist also, including visible light, but I guess those residues are not enough for your purposes.

Can I assume assume UVA is included since it is a longer wavelength than UVB?

You can assume, of course, but you might actually be very wrong, as I explained.

Moreover, according to the information on the site, it is much safer to assume that you will have neither UVA, nor UVB.

  • Yes -- I believe you are right. The package mentioned UVB indirectly and fooled me. The mini halogen fixture came with a snake habitat kit (we're using for a lizard), and I guess snakes don't need UV as much. – rrauenza Jul 16 '20 at 7:15
  • I do not know the UV requirements for snakes, sorry. – virolino Jul 16 '20 at 7:39

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