There are
many lights on the market today, many aimed specifically for reptile
keeping. Not all however are suitable for Vitamin D3 production.
Flourescent
Lights
Strip
lights contain low pressure mercury vapour which when iodized (electric
current passed through it) emits UV light. This energy (UV light)
is then absorbed by a thin coating of white phosphor on the inside
of the bulb. The white phosphor uses the energy from the UV light
to emit visible light (it fluoresces). Some energy is wasted as heat
but m
ost
is changed to visible light.
The colour of light emitted (cool white, soft tone, Beauty Lights
etc) depends on the
chemicals
mixed in with the phosphor powder. Normal glass blocks 95% of UVB
and 30% of UVA therefore any UVB and a noticeable amount of UVA not
changed to heat and light by the phosphor coating is effectively absorbed
by the glass casing.
Examples of this type of bulb are cool white office lights, kitchen
lights and aquarium lights.
These types of bulb do not produce sufficient UVB however they
are useful when used in conjunction with a UVB producing light to
increase the amount of light in vertical enclosure.
Specialist Reptile UV Flourescent Lights
The sleeves
of these bulbs are made of quartz instead of glass. Quartz allows
UVA and UVB to pass through freely. In addition as the aim is to produce
UV light the phosphor coating is thinner. Consequently as less of
the UV created by these bulbs is absorbed by the phosphor coating,
UV producing fluorescents that produce a decent amount of UVB (1-5%)
aren't very bright (and have a lower CRI) and conversely bright UVB
producing fluorescents do not produce much UV.
As well as UV light, iodized Mercury Vapour also emits some green
and blue visible light. That is why UV lights look grey/violet to
the eye.
It is advisable
therefore, for sun loving species, when using a UVB producing fluorescent,
to also use a white light emitting source as well - this will give
your diurnal reptiles both the UV and the bright light they need.
In addition
always maximise the amount of light reaching your reptile by using
a reflector.
The Chameleon
Information Network recommend using two Reptile UV producing flourescent
bulbs in each enclosure. We have tried one UVB, one UVB and a 2.0
UV, and one UVB and a normal flourescent and have not noticed any
adverse effects with any of those combinations. We would normally
only use one UVB bulb in a horizontal shaped enclosure where the animal
is never far from the bulb or when overheating can be a problem. In
vertical enclosures two bulbs are better.
Full
Spectrum Light
This is
a common term used for Incandescent (tungsten) Reptile Basking
Lamps and Plant Lamps. This is misleading in that only visible light
and a very small amount of UVA is produced. Basic tungsten bulbs do
not produces UVB.
The term full visible light spectrum would be more accurate.
Several
Reptile basking lamps available are covered in "rare earth elements".
These are simply normal household bulbs coated with an element to
remove the yellow light therefore slightly altering the way the environment
is perceived (usually things seem slightly brighter).
It is far
better and cheaper to use a household incandescent in conjunction
with a UVB-producing fluorescent. Full visible spectrum will be produced
as well as UVA and UVB.
This type
of bulb includes Reptile basking lamps, household bulbs, reflector
bulbs, plant gro-lux bulbs and Reptile "day-light" bulbs.
This type of bulb does not produce UVB
Halogen Lights
Tungsten
halogen lamps are increasingly being used because they are a small
and highly efficient light source. Halogen gas is used to capture
vaporised tungsten atoms and replace them on the filament thus allowing
the filament to run hotter and longer than conventional tungsten bulbs.
Because of the higher operating temperature significantly more amounts
of ultraviolet (UVA) as well as visible light is produced. To maintain
operating efficiency the bulb wall must be hot (over 260'C), so it
is made of quartz which withstands the heat better than glass, but
absorbs less UVA. A significant portion of energy generated is within
the UVA wavelength.
The Health
and Safety Executive in the UK provide the following advice on the
use of halogen lights in the work place:
"It is generally recommended that all tungsten halogen lamps
should either be fitted with an appropriate UVR filter, or a bulb
with a glass outer element. In particular, the use of unfiltered desktop
lamps should be discouraged if they are used for more than 2 hours
per day and are sited within 0.6m of the user. If a lamp is fitted
with a double-walled bulb, but the outer wall is broken, it should
not be used.
UVR exposure caused by some desktop tungsten halogen lamps can be
comparable in some instances with levels of solar UVR in terms of
its erythemal (sun burn) and potential carcinogenic (cancer causing)
effects."
Compare
the 2 hour period and 0.6m minimum distance cited with a typical Chameleon
set up with a photo-period of 12 hours. This would increase the exposure
dramatically. Clearly unfiltered light could produce a serious health
risk. In addition consider that the filters often used only block
light below 360nm. The UVA range is from 400nm to 320nm and therefore
a significant range of UVA is still allowed through.
We do use
small filtered halogen bulbs to create a basking spot for Stump Tailed
Chameleons and have bred them frequently without any adverse effects.
Halogens can produce a small, fairly hot basking area without significantly
effecting the temperature in the rest of the vivarium. So are useful
in smaller vivariums to allow the animal to thermo-regulate.
It should be noted though, that these vivariums are well planted with
many hiding places and a layer of dead leaves to provide further shelter.
These
lights must not be used without a UV filter.
Mercury
Vapour Lamps
(eg Powersun and UV Heat)
When
first released these were going to change the way we keep chameleons.
This is true to some extent because they provide UVB for a much greater
distance than the traditional flourescents. This meant a "free
range" set up could be provided with sufficient UVB covering
a greater area and heat, all from one bulb.
The problem
with these bulbs is the same reason as the benefits. They are very
powerful. In reality many chameleons do not bask for huge amounts
of time. Possible exceptions are chameleons that come from areas,
which are devoid of vegetation at certain times of the year. Examples
being Veileds, Oustalet's and Verrucosus.
In summary
they can be a good lamp if used in the right circumstances (large
enclosures or free range) and with the right species of chameleon.
Note
of caution
Several keepers have noticed reduced fertility and deterioration
in the general health of Panther Chameleons kept under high powered
(100w plus) mercury vapour bulbs. It has not been proved that the
bulb is to blame but the animals in question improved when the lighting
was replaced with Zoomed 5.0 tubes. For this reason we suggest very
careful monitoring when using these bulbs.
Additional
Lighting Characteristics
CRI
CRI or
the Colour Rendering Index is used to compare the colour of an object
viewed under artificial light compared to its colour when viewed under
natural sunlight at noon. At noon the CRI is 100. The closer to 100
the CRI the more natural objects look.
People who suffer from depression throughout the winter but are fine
throughout the summer are responding to the change in the CRI. The
higher the CRI the better things look to us and to our reptiles.
Kelvin
This is
the colour temperature (ie warmth or coolness).
When metal is heated, the colour of light it emits will change. This
colour begins at red then changes to orange, yellow, white and then
blue-white and finally blue. The temperature of the metal in Kelvin
is used to describe the colour. Obviously the lower the more red and
higher blue.
At sun rise the sun is approx 1,800 Kelvin (red/orange). This increases
as it rises and changes from red to yellow to white at over 5,000
Kelvin at noon.
Preferred Kelvin for reptile lighting is from 5,000 to 5,500.
Lumens
Measures
the intensity of light leaving the light source.
Lux
Measures
the amount of light actually reaching a given point. The target distance
from the source as well as the intensity of the source effects this
measurement.
100w, 60w, 40w and 25w household bulbs have similar lumens (intensity),
but different lux. Consequently changing the wattage of a bulb used
to create a basking spot directly effects the light and heat at the
basking spot.
When creating a basking spot the aim is to create a bright area as
well as a hot area as reptiles associate bright light with heat. If
a dimmer stat is used with for example, a 100w bulb the bulb may only
be burning very slightly for the area beneath it to reach the required
temperature and consequently would produce very little light. It would
also gradually warm up the rest of the enclosure resulting in a reduction
of the thermal gradient therefore effecting the animals ability to
thermo-regulate properly.
A better option would be to use a lower wattage bulb that needs burn
brightly all the time to achieve the required temperature which consequently
would also create the desired bright spot as well.
What
the numbers on Reptile Lamps mean
Numbers,
such as 5% or 10%, or in decimal form,8.0, 5.0 or 2.0, refer to the
percentage of UVB light emitted within the total amount of light energy
produced. i.e. 10% means 10% of all light emitted by that bulb is
in that given range.
These numbers
can not be used to determine which bulbs produce most UV for the reptile
unless the total amount of light emitted is also given.
Length
of UV Production in bulbs
Over time
the amount of UV light emitted drops significantly although visible
light is still produced. Tube manufacturers recommended that you replace
the tube at least every 12 months (most suggest between 6 - 12 months).
Usually after 12 months the tube is no different from a standard fluorescent
tube in terms of UV output. A good way to ensure that you change your
bulb regularly is to write the date it was first used on the end of
the tube in a permanent marker. This way it doesn't matter if you
move the tube, change setups or whatever, as you'll always know when
it's time for a change.
A fresh UV tube is particularly important for rearing baby chameleons
as the demand for calcium in their rapidly growing bodies is much
greater then when they are adults.
We also suggest breeding females are provided with new lights more
frequently than the manufacturers suggest.
Other lamps
such as sunlamps have been recommended for a limited period each day.
The problem with this setup is if the light is on a timer the chameleon
may not be under the light when it switches on. Also this type of
bulb would create an abnormal period of light intensity which could
cause stress and stress related health problems.
Using less
effective D3 lights, such as the purpose build reptile D3 flourescents,
for standard photoperiods result in sufficient doses of UVB.
Look out
for updated information regarding UV lights and ageing results
here
Getting
UVB to the required place
Once a
UV bulb has been obtained the next problem is to ensure the beneficial
wavelengths actually get to the Chameleon.
UVB from
many specialist Reptile UV fluorescents do produce sufficient UVB.
The big problem is getting UVB to the reptile as so many substances
(including air) absorb UVB and a lot of UVA.
UVB will
not travel through most types of glass. Only horticultural glass used
in some greenhouses allow UVB to pass through.
Therefore
placing a UV light outside a fishtank or glass vivarium is a complete
waste of time and is dangerous to the chameleon (fish tanks should
not be used to keep chameleons in anyway as they do not have sufficient
ventilation, even with all mesh tops!)
Window
glass also blocks UVB. Putting your Chameleon on a plant on the window
sill (or conservatory) will not expose it to any UVB but does allow
some UVA through which can have a beneficial effect on their mood
(see earlier notes on UVA).
Please note that windowsills in direct sunlight can get very hot.
Always ensure your Chameleon can move into a cooler area. Water should
also be made available in suitable quantities (see WATER)
Most plastics
filters UV light. Even mesh filters up to 30% of UVB.
Safety
Note: We do not recommend the use of cages around the UV bulb
or the basking lamp. We have found that if a Chameleon can reach the
cage it is very likely to climb on it and often hang upside down from
it, thus exposing its soft underbelly to excess UV and heat at too
close a distance. This often results in burns that can be fatal. All
of our UV bulbs and spot bulbs are situated in such a way that the
chameleon can not reach them so the need for protective cages is eliminated.
Sunlight
There is
no substitute for the real thing. With the possible exceptions of
the forest floor dwelling chameleons such as the Rhampholeons and
Brookesia all Chameleons fair better when exposed to natural sunlight.
Whenever
possible regular exposure to natural unfiltered sunlight is highly
recommended.
A few pointers below should however be born in mind:
The chameleon
must be able to retreat from the direct sunlight to somewhere cooler.
Natural plants work well in this respect as they not only provide
shade but the humidity produced from the leaves also cools the air
immediately around them.
Drinking
water should be provided at all times (we have observed fussy drinkers
drink huge amounts from drippers in outside enclosures when they would
take little interest indoors). Misters (which can now be bought cheeply
from garden centres) should be used in hot weather to prevent the
chameleon overheating. The mister should only cover part of the enclosure
so the chameleon can move in and out of the mist when it wants to.
Chameleons
should be housed in a suitable enclosure to prevent escape or attack
by predators (this includes mesh small enough to stop bees and wasps
entering if your garden has many). Glass should not be used on outside
enclosures.
Extremes
of temperature are to be avoided.
Screen
cages designed so that they can be taken outside are particularly
suitable. If the chameleon can be taken outside in its own enclosure
on suitable days this helps reduce stress associated with the chameleon
getting used to his new surroundings.
Current
lighting research
We have
recently invested in a UVB testing meter. The aim is to test the UV
lights curently available and how best to set them up to optimize
the UVB available to our chameleons.
We are
testing how reflectors and various meshes effect the amount of UVB
reaching the target. Over the coming months we will also be testing
how the resultant UVB drops off with age.
As
this is an ongoing project we will be posting links to pdf files with
our current results. Eventually they will be added in full to the
website but this method allows us to update our findings quickly and
regularly until finalized.
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- General
Introduction to the testing and the measurements we are taking.
- Review
of Zoomed 5.0 Reptisun and Repti-glo 5.0 and 8.0 Lamps
- Table
to work out the UVB reaching your basking spot
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