kingofnobbys":344spyiv said:
I'll continue advising about 200 microW UVB flux / sq.cm at the basking spot and cool zone about 1/3 that with the tube no more than 2/3 the length of the viv.
As these levels are fine and I'm yet to see proof that lower levels (in UVB and UVA flux or in UV-Index if one insists on using UV-Index as the "measure") are appropriate for pogona species.
Do not not feel it better to simply suggest a distance instead? Why complicate it for someone who is seeking advice. Either they need an expensive instrument to follow your advice, or they need to look online to find a chart.
the charts are there (online and easy to find, at manufactures sites ,or on message boards) , so that's no real excuse.
The beauty of having a chart or graph of the "as new" output is that this gives owners the opportunity to monitor the performance of their globes or tubes UVA & UVB performance, and to know exactly when the output has decayed to below say 40% the "as new" performance , I use 40% on UVA and UVB flux at a standardized distance (in my case I choose 12") as my time to downgrade to a species who needs less UV or to toss out and replace.
A rapid drop in UVB with an increase in UVA with a decaying phosphor coating will not be picked up by a UV-Index meter as it's not designed to detect UV in a quantitative way but measures UV across A and B bands In a very qualitative and subjective manner ( modeling approximately the UV response of HUMAN SKIN ).
I invite you to get hold of some more recent scholarly articles on UV - emitting LiCaBO3:Gd3+ phosphor decay , I refer you to wileyonlinelibrary.com/journal/luminescence where there studies of how phosphors decay and how the UV spectra of their excitation emissions over time as the phosphors decay / breakdown that make very interesting reading (even if very technical and scientific and require deep knowledge of materials , chemistry and physics).
This has been a long term interest of mine .
Therefore the user could easily be lulled into a false sense of security thinking their tube is performing fine when in fact the phosphors are decaying and the UV emission spectrum is shifting and changing , and the reptile is no longer receiving sufficient UVB.
I have a UVA and a UVB meter that I use regularly. These instruments are not that expensive and IMO well worth having in hand in your "kit"..
Of course you could provide a chart, but why not simply state a distance range (much like Arcadia has done) as opposed to a range immeasurable by the average person seeking advice.
kingofnobbys":344spyiv said:
company web sites don't always reflect the full scope of the specs and useage guidelines provided with their products. To include everything makes for a very detailed by confusing webpage and those who set up the webpages are usually not the engineers but marketing / sales people who have a "different" focus.
It's actually usually the opposite. The packaging is simplified and the webpage is detailed. And It's not fair to assume that whoever put together Arcadias site didn't know what they were doing. It's a big assumption.
Here is a quote from their lighting article that lends credence to the fact that their guide wasn't just haphazardly put together.
>> I prefer to see the scientific data that was used and make my own assessment , I note they have not cited any scientific papers.
I hold myself to high scientific standards regarding providing citations in correct scientific literature format and don't think it's unreasonable expect the same from the engineers and scientists employed by companies like Zoo Med, Exo Terra and Arcadia Reptile , as indeed was my management's expectations when I was working as a researcher for BHP and my expectation when I became a senior and then a principal engineer, and similarly when I was working at my local university..
Here at Arcadia Reptile we decided to re-write the lighting advice that was being given. We used science when doing so rather than generalisations. Now, keepers are able to use the published outputs of lamps to re-create the UV levels (UVI) of species in the wild. We studied the wild UVI in the environments of common species and we looked at the habitats of popular species with the aim of understanding how each species used solar energy. We looked at skin thickness in each species and checked this with tetrachromacy (the reptile’s ability to see UV light), aiming to find how much light would be available per species in the wild. We also discovered what is now known as leaf or rock scatter illumination. These are the terms used to describe light that travels down from the forest canopy or passes through holes and gaps in rocks. This means that those species which were traditionally classed as low light requiring species, in fact are now known to use UV levels efficiently.
Either way, I think it's bad form to offer old advice simply because your bulbs you bought awhile ago still say that. The manufacturer changed their recommendation for a reason, and it is only wise to take that into consideration.
Do I think 200 mw at the basking surface is too much? No, not really. But my concern is too much throughout the tank. 150, 200, 250 mW, fine, as long as their is a gradient to get away from. And the higher that basking number goes, the harder it is to achieve that low gradient to 0.
>>> so long as the dragon has access to a hide , It has access to zero UV if it needs to seek "shade" , just as having an area not illuminated by the UV source provides very low UV or even zero UV.
…. obsessing about level of uv in the "shady" area is really just muddying the waters IMO.
-Brandon
-Brandon