Re: Hey Roger.... UVB meters

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Posted by Mr. D on January 11, 2003 at 12:08:00:

In Reply to: Hey Roger.... UVB meters posted by Phnoxx on January 11, 2003 at 09:52:50:

:The meter I have is the Solarmeter Digital Ultraviolet Radiometer, model 6.2 UVB It's range is 0 to 1999 uW/cm^2, and is sensitive from 280 - 320 nm (part of the UVB range). Those of us who have them can tell (by multiple comparisons of readings from new UVB tubes) that they hold their calibration well; the readings have been consistent for a couple of years now.

:They cost about $150. I can't find it right now, but I recently noticed that an on-line herp supply store offeres them now.

:What do you-all think of my reasoning about the benefits of low-heat UVB (tubes) in combination with thermostatically-controlled heating and lighting?

:Roger

In all honesty, having seen the readings I got with my 6.2 I think that fluo output is too low - or at least not high enough to easily allow for D3 synthesis. My thinking is that the readings I got during mid summer over the course of the day suggested that even in direct shade the uW/cm^2 readings were upwards of 60. Since igs travel between direct light and shade constantly they are receiving much greater amounts of exposure than that over the course of the day. Mid day readings at peak sun here were upwards of 250 uW/cm^2. In natural habitats, I can only imagine that these readings would be much higher - I haven't gone looking for actual readings for those locations as of yet.

Flood vaps produce roughly 50 uW/cm^2 at 12" - and less the further away due to the decay rate of UVB. Since D3 synthesis in igs, much like many other species of animal (human included), is self-regulating no harm will come from a constant exposure of 50 +/- uW/cm^2 from a D3 perspective. The same goes for radiational UVB exposure. From everything that I've read, these guys actually SEE in the UV spectrum. That being the case, I believe that they are much better designed to handle the exposure. One of my concerns with fluo tubes is that an igs system is overworking to produce D3 because it isn't getting enouch UVB exposure. Much like stereo speakers. Speakers most commonly blow because they do not have ENOUGH wattage driving them and must work harder to produce sound waves. It's more difficult to tear a cone with too MUCH power than not enough....

Personally, what I would like to see is a bulb design - quite possibly in the "tube" style that produces the same UV levels as a vap and disperses it over a greater area - as a tube does - while producing minimal heat. This way, we are totally free to design enclosures in any manner without having to worry about combining UV exposure and basking heat etc. With this setup we'd be able to locate basking light anywhere we chose while still allowing for solid UV exposure.

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