MVB UVB

[mark1]

Facts about Mercury Vapor Bulbs - by: Bob MacCargar
I have at this time I have tested well over a 130 Reptile Mercury Vapor bulbs for UVB out-put, UVB decay, and failure rates
MV bulbs produce 3 times more UVB in the 290-300 (D-UV) nanometer range than “tube” type UVB bulbs of the total UVB out-put. 10uW/cm2@12’ from a MV FLOOD lamp is equivalent to 30uW/cm2 from a tube lamp.

In a recent study by Dr. Gehrmann and associates, of spiny tailed iguanas, showed that MV SPOT lamps brought the hydroxyl (OH25) levels in the blood equal to those found in the wild. Interestingly the majority of creatures in this controlled study also preferred to bask under the Mercury Vapor SPOT lamps in comparison to the alternative UVB light and heat source

 

[jaizei]

Facts about Mercury Vapor Bulbs - by: Bob MacCargar
I have at this time I have tested well over a 130 Reptile Mercury Vapor bulbs for UVB out-put, UVB decay, and failure rates
MV bulbs produce 3 times more UVB in the 290-300 (D-UV) nanometer range than “tube” type UVB bulbs of the total UVB out-put. 10uW/cm2@12’ from a MV FLOOD lamp is equivalent to 30uW/cm2 from a tube lamp.

In a recent study by Dr. Gehrmann and associates, of spiny tailed iguanas, showed that MV SPOT lamps brought the hydroxyl (OH25) levels in the blood equal to those found in the wild. Interestingly the majority of creatures in this controlled study also preferred to bask under the Mercury Vapor SPOT lamps in comparison to the alternative UVB light and heat source

This appears to be from 2005, the 'tubes' referenced would have been T8 or T12. The MVBs he's referencing have changed or are no longer being produced. What he is describing is why UVI became the standard measurement for UVB lamps instead of uW/cm2

 

[mark1]

point is not which is best, the point is, mercury vapor bulbs are not a poor source of uvb....


How much UV-B does my reptile need? The UV-Tool, a guide to the selection of UV lighting for reptiles and amphibians in captivity

 

[ZEROPILOT]

point is not which is best, the point is, mercury vapor bulbs are not a poor source of uvb....


How much UV-B does my reptile need? The UV-Tool, a guide to the selection of UV lighting for reptiles and amphibians in captivity

I do believe that research that you've found. And I highly appreciated your content.
However, a few years ago I did my own tests with 6 MVB placed on 6 Chameleon cages with my uv meter and a non contact thermometer. The uvb readings varied wildly. From light to light and to some extent, the same lights from day to day. So did the heat levels and the light output itself. 6 bulbs. None the same. And three of the bulbs had some sort of heating up/start up period where they just glowed for a few minutes before starting. Then burned like a blow torch. Two stopped working altogether and one of them seems to have gone "super nova" on me and scorched the plants 10" away. The Chameleon in that cage was luckily not barbecued.
I wanted to like them. I'd spent over $300 on them. But they really let me down.
When I warn people not to use them, I'm not parroting information. I'm using my own.
My experience is that they're expensive and do nothing well. At least not consistently. And they may be dangerous.
My experience only.
Certainly it's not everyone's experience. They're still being sold. And I understand that Chameleons are a lot more fragile than tortoises.
I warn especially since I've never had any issues of any sort with any of my T5. So those I do reccomend in general.
I don't usually elaborate on why I'm not a fan of the MVB

 

[mark1]

Ed, your experience is noteworthy, successfully keeping chameleons would be excellent experience with lighting.........

none of the research is mine , i just take zoo meds word for it ..... they have been doing uvb for like 40yrs , along with gary ferguson ...i've always understood lighting was a big deal , long before reptile light became available , at one time i used metal halide street lights in a monitor enclosure, i have no idea if they added anything other than they were very bright ........ as Jazie said, they are all better at it today than they were 10yrs ago ..... they have t5 fluorescents now that can put uvb out to further distances than the t8, i don't know if they have a better spectrum .... they are developing led technology ....... zoo med claims their mercury vapor lights, and metal halide, put out similar uvb in the 300nm range as their fluorescents, which to my understanding ,trusting others research, is the spectrum range needed...... no single light is enough , i personally believe mercury vapor lights can serve a purpose , and can be used......are they better , assuming zoo meds research is true, it depends on the situation.....i use them outside on timers in the spring when winter makes a come back ....... i have used and still use mercury vapor , fluorescent tubes, coil bulbs, che's, and infrared heat bulbs..... all uvb is dangerous, from any of them........knowing the dangers is the only way to do/use anything safely...... i've personally never experienced a turtle or tortoise with the eye problems i read about that are attributed to lighting, i do believe the eye's would be the first place to have a problem from improper uvb exposure..........

if you ever see an overlay of any kind of artificial light and sunlight , it appears to me, nothing artificial even remotely resemble sunlight........ keeping them outside i think validates that this artificial lighting is definitely not sunlight ......

the problem/danger i believe with mercury vapor and metal halide lights is distance and heat ..... there are ways to manage that.......

is a low "dose" of uvb for a long period equal to a high dose for a short period ?? is leaving a fluorescent uvb bulb on all day in an enclosure safe?? can a reptile under artificial lighting be over exposed to uvb, and produce too much d3 ??? .

 

[Alex and the Redfoot]

Hi, @mark1 !
You may look at this old thread, started by Dr. Frances Baines (lilacdragon) - https://www.tortoiseforum.org/threads/infrared-sunlight-vs-basking-lamps.84606/ and also look through some posts on topic made by markw84. They to some extent explain why metal-hallide lamps and MVB are not suitable for tortoises (it has less to do with UV part of spectrum, but with IR part).

Short-term exposure to high UV output and long-term exposure to low UV output are not the same thing due to physiology of D3 synthesis. Overproducing D3 is unlikely due to built-in safe guards. More on that here: http://www.uvguide.co.uk/vitdpathway.htm

 

[wellington]

point is not which is best, the point is, mercury vapor bulbs are not a poor source of uvb....


How much UV-B does my reptile need? The UV-Tool, a guide to the selection of UV lighting for reptiles and amphibians in captivity

Except it has been proven here, that they still cause pyramiding. Did they do the tests on tortoises? If not, then it does us no good!

 

[mark1]

best i can tell pyramiding due to IR has little to nothing to do with health, it has to do with poor conditions for keratin formation.... IR is no more dangerous than UV...... either can be a problem ...... IR is important to reptiles , doubtfully they know they are making d3 when they are basking , but undoubtedly they know they are warming .........


as i said earlier the problem with mercury vapor and metal halide is heat(IR) and distance ........if pyramiding is a concern , finding a wattage and range for a tortoise would be much harder than with a fluorescent and a separate heat source(IR) , for turtles it's no problem, they don't pyramid like tortoises .... ...... zoo med says you can get comparable uvb with a powersun 160 watt mv at about twice the distance as a t5 reptisun 10 fluorescent tube ....... they do show the reptisun has much more uvb out of the useful d3 conversion range, is that uvb used in determining UVI ...

as far as "low" uv , i'm thinking of uv at around 300nm just less intense ....... i'm not understanding why uv at 300nm at a lower intensity would not promote the same conversion 300nm at a higher intensity does ....... would be like saying at 10 am the uvb is not useful because at 12pm it is more intense..... do you think IR plays any part in this process ? i think it possibly does, breaking chemical bonds i think requires heat input ???

 

[Alex and the Redfoot]

best i can tell pyramiding due to IR has little to nothing to do with health, it has to do with poor conditions for keratin formation.... IR is no more dangerous than UV...... either can be a problem ...... IR is important to reptiles , doubtfully they know they are making d3 when they are basking , but undoubtedly they know they are warming .........


as i said earlier the problem with mercury vapor and metal halide is heat(IR) and distance ........if pyramiding is a concern , finding a wattage and range for a tortoise would be much harder than with a fluorescent and a separate heat source(IR) , for turtles it's no problem, they don't pyramid like tortoises .... ...... zoo med says you can get comparable uvb with a powersun 160 watt mv at about twice the distance as a t5 reptisun 10 fluorescent tube ....... they do show the reptisun has much more uvb out of the useful d3 conversion range, is that uvb used in determining UVI ...

as far as "low" uv , i'm thinking of uv at around 300nm just less intense ....... i'm not understanding why uv at 300nm at a lower intensity would not promote the same conversion 300nm at a higher intensity does ....... would be like saying at 10 am the uvb is not useful because at 12pm it is more intense..... do you think IR plays any part in this process ? i think it possibly does, breaking chemical bonds i think requires heat input ???

IR itself is divided in several bands. And there are IR-A subbands which are absorbed by water molecules. In the atmosphere, it's filtered by water vapour and doesn't reach the ground and tortoise shells. But in captive conditions it's the water in blood vessels in the shell growth zones. This results in local overheating and excessive desiccation of the growth zones. That is supposed to contribute to pyramiding.

For D3 conversion both UVB and heat are needed (not IR per se). Intensiveness of UVB is a bit tricky: too low is not enough to trigger biochemical response due to filtering in skin scales. Too high levels will trigger "guard rail" mechanisms and should not do harm (except for the eyes). Very-very short exposure to UVB perhaps won't trigger D3 synthesis reactions (chemical processes aren't immediate).

 

[mark1]

i really know very little about this stuff , my understanding i'm sure is less than basic .....i need someone to draw me a picture, i believe i do understand what these charts are saying........i think something like 99% of the heat you feel from the sun is IR??

this is the spectrum of sunlight reaching the earth

this is from a company that makes heat lamps for medical

here's a comparison , 160 watt mercury vapor.....sunlight in july in Wales, UK........ and a halogen light.......

i also believe you could pyramid a tortoise with a che, or halogen light ....... from the charts above it appears to me the halogen light appears far more desiccating than the mercury vapor light??

 

[wellington]

i really know very little about this stuff , my understanding i'm sure is less than basic .....i need someone to draw me a picture, i believe i do understand what these charts are saying........i think something like 99% of the heat you feel from the sun is IR??

this is the spectrum of sunlight reaching the earth

this is from a company that makes heat lamps for medical

here's a comparison , 160 watt mercury vapor.....sunlight in july in Wales, UK........ and a halogen light.......

i also believe you could pyramid a tortoise with a che, or halogen light ....... from the charts above it appears to me the halogen light appears far more desiccating than the mercury vapor light??

I moved the discussion to its own thread. It was taking over the other one
Yes, the halogens are not recommended as they can cause pyramiding even in the most humid conditions and the che's s is meant for ambient heat or night heat not basking.
Tom figured out the mvb and halogen still causing pyramiding some years ago. Even in the highest humidity, some pyramidimg was still happening with the two lights mentioned.

 

[Alex and the Redfoot]

Thanks for moving us in the separate thread (I was going to ask about it )

1. First graph you have posted shows "gaps" in the sunlight - in IR-A part you can some of them. That's the wavelengths absorbed by water molecules (in the atmosphere or in the living tissues).
2. You are right, that perceived warmth from sunlight comes from IR radiation. And partially from long wavelength IR (IR-C) which is emitted by warm objects around like stones and ground, but absent in the sunlight.
3. Allmost all lamps emitting in IR-A spectrum don't have this gaps in spectrum (as on the second graph). That means, that normally filtered by atmosphere wavelengths are projected and absorbed by water in tissues exposed to it. There are very expensive water filter systems which can absorb these wavelengths from artificial sources, but it's almost impossible and not economically feasible to use them in vivariums.
4. The third graph lacks IR part of spectrum, but yes - halogen and metal hallide lamps are more disiccating.
5. Yes, you are right, that CHE or halogen lights can cause pyramiding. Almost any heat source due to incorrect distance or it's emitted spectrum can dry out keratine and cause pyramiding. With some efforts even radiant heat panels can, I believe.
6. Specific spectre of MVB is because of mercury and specific coating of the lamp. It's very close to that of other mercury based light sources. I can't find full spectrograms for MVB to check what is their IR-A output - so I might be wrong about it... However, looking at power distribution chart (datasheet on Arcadia website) it feels like a tricky task to use them for basking and as a UVB source at the same time...

UPD: Gotcha! Here is the post with graphs and explanations from markw84: https://tortoiseforum.org/threads/arcadia-deep-heat-projector.178152/#post-1776631

 

[mark1]

not exactly sure how to compare the graphs you linked , one has no units , i assume w/m2 ? the other is watts to micrometers ? i find this a easier comparison....

not exactly sure about what "gaps" have to do with this or what they are ? at no point does a mercury vapor bulb even approach any ir from the sun , these reading are on the ground in Wales ??? wales is pretty much the same latitude as newfoundland ??? i believe the guy that makes the medical infrared bulbs said the most desiccating (water absorbtion) range of IR is above 1100nm?????

i'm not advocating using or doing anything i do ...... i don't disagree that fluorescents offered as a completely separate source of uvb from the heat source is a simple solution ........ i do disagree that mvb's any poorer of a source of uvb than anything else ...... although imo the only good source of uvb for reptiles is the sun.......one thing you needn't know anything about um, mm2 , W, m2 ,nm, is none of these artificial lights even remotely resemble the sun.....

i kept redfoots and elongated tortoises for at least 10yrs, they were provided nothing more than bath and kitchen fluorescents for 7-8 months of the year.........., the other 4 -5 months they had the sun.....

 

[mark1]

there was an experiment done at the university of veterinary medicine , vienna , austria....... it was submitted in 2002 , they raised smooth and pyramided tortoises using humidity ...... here is the lighting they provided both....

Each terrarium was illuminated by three different light sources. Under the top pane, a 150- W HQI-lamp (Teclumen, Castel Coffredo, Italy) was fixed, which supplied the animals with the necessary light intensity for activity. The connected intermediate unit (containing the transformator) was located outside of the terraria. At the left side of the terrarium and about 25 cm above the ground, a halogen heater lighted and heated the area below. Also at this height, an ultraviolet radiating fluorescent tube (UV-A and UV-B, Reptisun 5.0; Zoo Med Laboratories Inc., San Luis Obispo, CA, USA) was also provided at this height. The HQI-lamp was on 11 h daily from 8 am to 7 pm. Heating light and UV-tube were activated for 3 h each morning (9–12 am) and 90 min each afternoon (3–4.30 pm). At the bottom of the central area of the terrarium 7000 lux, and under the halogen lamp, 14 000– 15 000 lux, were measured, respectively.

a 150watt HQI lamp is a 150watt metal halide light..... a halogen heateris an infrared heater , and a fluorescent zoo med reptisun 5.0...... the metal halide lamp was left on 11hrs per day......

here is the spectrum of a mercury vapor bulb taken out further..... i imagine they stopped at 750 in the other graph , as their MV lamp really produced minimal infrared past 700nm

 

[Alex and the Redfoot]

I'm not here to argue either or to challenge your experience. More of "better understanding while explaining" thing.

The graphs I referenced in markw84 post show pretty much the same thing - radiance is roughly watts per area (how much of lamp's output is emitted in certain part of spectre). That graph, that you find easier for comparison, unfortunately cuts of spectrogram at visible/IR boundary (X-axis ends at 750 nm on the right).

"Water absorbed" range of IR should be pretty narrow in fact. Specific chemical elements absorb narrow wavelength bands and emit specific wavelengths when heated. That's the basis for the spectrophotometry.

Can you post the links to the research you mentioned? I would be an interesting read, I think.

You are right, that MVB can be a good source of UVB. However, it's hard to balance heat/light properties of these bulbs to avoid overexposure to UV and IR-A and provide a warm basking spot at the same time.

Absolutely agree, that artificial lights are no match to the natural sunlight. There are a few full-spectrum lights closely approaching sunlight spectre but they still lack the "atmosphere filtering" of the specific wavelengths.

Redfoots are "different beasts" to many other species as they can ingest some dietary D3 due to being omnivorous. 4-5 months of outdoor living maybe sufficient to synthesize and deposit required D3 in fat tissues. I know little to none about elongated tortoises (their habitat and diet) but have no reasons not to trust you

 

[mark1]

Influence of environmental humidity and dietry protein on pyramidal growth of carapaces in African spurred tortoises (Geochelone Sulcata)
Near infrared (NIR) or short-wave infrared heaters operate at high filament temperatures above 1,800 °C (3,270 °F) and when arranged in a field reach high power densities of some hundreds of kW/m2. Their peak wavelength is well below the absorption spectrum for water, making them unsuitable for many drying applications
the absorption spectrum for water has its peak at around 3 μm. This means that emission from medium-wave or carbon infrared heaters is much better absorbed by water and water-based coatings than NIR or short-wave infrared radiation

 

[Alex and the Redfoot]

There you can find absorption windows for IR in the atmosphere: https://en.m.wikipedia.org/wiki/Infrared

It's clearly seen, that there are several wavelengths absorbed by water molecules. IR-A and IR-B cover range from 0.78 micron to 3 micron and we have several absorption windows there.

At the same time, if I can correctly interpret graphs here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3169023/ , dried skin and keratine have absorption peaks in IR-B and IR-C bands. That means, that the whole tortoise shell will warm up under this infrared light sources, while IR-A results only in localized heating of water-containing tissues (such as blood vessels in the growth zones) without deep heating.

 

[mark1]

honestly , i did look at your link , the dinosaur one, i'd need to go back to school to read it ...... visually comparing graphs i do know enough to know they have to be the same units of measure.....

not sure where this is going ???? dinosaurs and water in the air absorbing light wavelengths is certainly not where i started......

there is a lot more in our atmosphere than water absorbing/reflecting sunlight, ozone, pollution and co2 off the top of my head ......

my original reply was about mercury vapor lights , this person bought one and was told they were useless ...... i disagree ..... at minimum they can be used in the place of an "incandescent flood bulb" ...... an incandescent light emits more IR in the range that is absorbed by water than does this persons mercury vapor light ..... to me that means at an equal temperature distances an incandescent bulb is more "desiccating" than the mercury vapor uvb light they have ......

this is my simple minded take on this..... in order to evaporate water , you need to heat it , in order to heat it , it needs to absorb energy the wavelenghts absorbed BEST by water are

this graph is from a guy with a phd in physics , a physicist named Daniel Merthe .... the NIR spectrum would be where the red line is, they do make IR tankless water heaters , i assure you they do not use NIR ........


my unpopular reply to the original poster would be to put their mercury vapor bulb at a distance to achieve the temperature they need , and either go to the manufacturers website and take their word for the uvb they're getting at the distance they put the bulb , or get a meter and check it themselves....... if your not getting enough uvb , use it as a heat source and go with the fluorescents for uvb........ heat is not an issue with a fluorescent bulb.......

 

[Alex and the Redfoot]

Yes, we went a bit too far Incadescent lamp don't output that much IR-A because of the temperature of the tungsten spiral, as I understand it. MVB - do (it's an electric arc in mercury vapour), so they are more disiccating even on larger distances.

The graph you posted may have a "smoothing" (averaging) on it, so small gaps might not be noticeable. And to be even more fun - the X axis is non-linear And Y axis looks like a log10 scale... Also heating large amounts of water is a bit different engineering task from heating a tortoise - I guess it's easier and cheaper to use broadband IR emitter with less absorption ratio than building a precise narrow band one.

And going back to MVB: different MVB lamps have different proportion in heat and UVB output (chameleon guys say that Megaray lamps are more hot, than ZooMed). No doubt, you can try to search for the right balance between basking spot temperature, UVI and IR-A output mangling domes (coating and diameter) and distance, lamp models and wattage and finally succeed. It's just can be harder for the new keepers than using incandescent + T5 combination. And maybe too time consuming for the experienced ones.

With large enough enclosures, non-prone to pyramiding species and certain tortoise age using MVB is much easier. Tom mentioned a couple of times, that you can use MVBs with adult Horsefields, for example. Perhaps, for other reptile species MVB work easy and flawless.

Yes, your answer is unpopular, however it's important to have the second opinion. There is a Reptile Lightning group on FB, I need to read more there (not only about MVBs, I'm curious about recent CFL measurements as well).

 

[mark1]

The graph you posted may have a "smoothing" (averaging) on it, so small gaps might not be noticeable. And to be even more fun - the X axis is non-linear And Y axis looks like a log10 scale... Also heating large amounts of water is a bit different engineering task from heating a tortoise - I guess it's easier and cheaper to use broadband IR emitter with less absorption ratio than building a precise narrow band one.

maybe you can make me a better graph ?????? if not maybe one of the chameleon guys can????

Daniel Merthe​

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