Solarmeter 6.5R worth its weight in gold!

CandyAss

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I just got my Solarmeter 6.5R and not a moment too soon! I knew my new UV light set up was stronger than my previous one, especially once I added the Arcadia reflectors to my Sun Blaze T5 HO fixtures, but wow! I'm using a Reptisun 10.0 in a 48" fixture. I had to raise it 20" above the basking area to get the UVI down to 2.9!
I haven't been able to find a definitive answer for what the Ferguson Zone should be for Mojave Desert Torts, but 2.9 still seems a bit high for my juvi's. If anyone has a recommended zone, I'm all ears.
I've been trying to compare UVI reports from Mojave, Ca and Las Vegas, Nv that correspond with the time of day of certain activities, like basking, in order to get an idea. But, I'm not a research scientist, so there's a wide margin for error. I have lots of hiding places and plants to offer shade, and a gradient that goes down almost to zero. Hopefully through watching their preferences and behavior I can dial things in better. But, again, I'm all ears if anyone has already done the work.
 

ZEROPILOT

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I Iove mine too.
It's also been helpful in trying to determine where to place the lights with other members throughout testing with my own equipment.
The newer T5 lights can blast through a screen top. Something that blocked out most of the UV from a T8.
A meter is the only way to get your UV dialed in.
I keep Redfoot tortoises who have a minimal need for UV and Chameleons which require a relatively high amount.
 

Tom

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I just got my Solarmeter 6.5R and not a moment too soon! I knew my new UV light set up was stronger than my previous one, especially once I added the Arcadia reflectors to my Sun Blaze T5 HO fixtures, but wow! I'm using a Reptisun 10.0 in a 48" fixture. I had to raise it 20" above the basking area to get the UVI down to 2.9!
I haven't been able to find a definitive answer for what the Ferguson Zone should be for Mojave Desert Torts, but 2.9 still seems a bit high for my juvi's. If anyone has a recommended zone, I'm all ears.
I've been trying to compare UVI reports from Mojave, Ca and Las Vegas, Nv that correspond with the time of day of certain activities, like basking, in order to get an idea. But, I'm not a research scientist, so there's a wide margin for error. I have lots of hiding places and plants to offer shade, and a gradient that goes down almost to zero. Hopefully through watching their preferences and behavior I can dial things in better. But, again, I'm all ears if anyone has already done the work.
So glad you like it. I mess with mine frequently just checking to see what outdoor UV levels are doing at different times of the day, with or without cloud cover, different seasons, etc...

There is much debate about what intensity of UV is needed and how long they need to be exposed to it. There are many variables to consider. I think a level of 2.9 all day will be more than sufficient to meet any tortoises UV needs. In your excellent climate, they should be getting sunshine on a regular basis for most of every year. This being the case, you probably don't need indoor UV at all. Add a calcium supplement with D3 twice a week, and some occasional Mazrui, and your tortoise will never get MDB.
 

iAmCentrochelys sulcata

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So glad you like it. I mess with mine frequently just checking to see what outdoor UV levels are doing at different times of the day, with or without cloud cover, different seasons, etc...

There is much debate about what intensity of UV is needed and how long they need to be exposed to it. There are many variables to consider. I think a level of 2.9 all day will be more than sufficient to meet any tortoises UV needs. In your excellent climate, they should be getting sunshine on a regular basis for most of every year. This being the case, you probably don't need indoor UV at all. Add a calcium supplement with D3 twice a week, and some occasional Mazrui, and your tortoise will never get MDB.
I’ve had this question in my mind Tom, not sure if you know the answer. But when A tortoise is kept indoor with a UVB Tube. How does the tortoise take/absorb the UVB is it something like is on The Air (including outside) or something like that?
 

Tom

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I’ve had this question in my mind Tom, not sure if you know the answer. But when A tortoise is kept indoor with a UVB Tube. How does the tortoise take/absorb the UVB is it something like is on The Air (including outside) or something like that?
The UVB rays are transmitted from the bulb to the tortoise's skin through the air. When the skin is warm enough, there is an enzyme in the tortoise's skin that converts vitamin D2 into vitamin D3 in the presence of UVB rays. If D3 is needed, it is used, if there is already enough D3, then it can be stored in the animal's fatty tissues to be used later. This is why they don't have to have UVB every single day all day. They can go weeks or even months with no UV at all and suffer no ill effects. With dietary D3, no UV is ever needed.
 

iAmCentrochelys sulcata

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The UVB rays are transmitted from the bulb to the tortoise's skin through the air. When the skin is warm enough, there is an enzyme in the tortoise's skin that converts vitamin D2 into vitamin D3 in the presence of UVB rays. If D3 is needed, it is used, if there is already enough D3, then it can be stored in the animal's fatty tissues to be used later. This is why they don't have to have UVB every single day all day. They can go weeks or even months with no UV at all and suffer no ill effects. With dietary D3, no UV is ever needed.
So if I’m understanding this part correctly in a closed chamber there’s would be more UVB in the Overall enclosure due to it being Closed? Sorry I was also thinking about that.
I might be totally incorrect.
 

Markw84

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A closed chamber does not have more UVB because it is closed. However, there can be more scattering into "shaded' areas by reflection, especially depending upon the color of the walls of the enclosure. UVB is light. It is just light with a wavelength shorter than violet light. So, like any other color, the amount in a closed chamber does not increase, but some may be reflected by the walls and then penetrate some shaded areas.

The amount of UVB needed for D3 production is not know. However, it does appear there is very little needed. The process for D3 production in our tortoises is that a the cells of the skin produces a cholesterol called provitamin-D. (@Tom - vitamin D2 is totally different and produced in plants) When exposed to light in the wavelength close to 297nm as a sharp peak, the provitamin-D is very quickly (few seconds or minutes) converted to Previtamin-D3. This all happens in skin cells. This previtamin-D3 is then isomerzed (molecules are rearranged) by heat applied to the skin over several hours. This is the process that takes time and requires heated skin. This isomerzed previtamin-D3 is now D3. That vitamin D3 is then released into the bloodstream where it is take up by a binding protein where it is taken into the liver and converted to calcediol. This is the 25-hydroxy-vitamin D3 that we look for in blood tests to check vitamin D levels. This calcediol is circulated around the body and creates a store of vitamin D for the tortoise. We do know in humans this has a half-life of about 2 weeks, so this store is available for a month or so. Some of the circulating calcediol that makes it way to the kidneys, is there converted to calcetriol. This is the active compound that controls the calcium levels and metabolism in the body. Calcediol is also taken up by the cells in many major organs and converted there to calcetriol which is instrumental in controlling organ function.

This does not mean we can then assume UVB is only needed for a very short period of time. The built in process that prevents overproduction of D3 in the skin is also UVB dependent. The process for isomerzing previtamin-D3 into D3 - which takes a long time in heated skin, also allows for the breakdown of excess previtamin-D3 with UVB exposure. So this protection mechanism happens with UVB exposure as well.

We do know in humans and mammals, that D3 That is not converted by the liver to calcitriol is then taken up by fat cells to be stored. However, it has not been shown that this happens in reptiles. Reptiles have a different energy store mechanism than fat reserves - using glycogen stores. So we do not know if there are fat stores of D3 in reptiles.
 

KronksMom

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This place is wonderful. Thank you all so much for constantly teaching me things that I didn't even know I wanted to know.
 

Markw84

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On a related note: The color of the skin of the tortoise may very well be an indicator of the level of UVB needed for all of this. We know in extensive studies of lizards and snakes, that the skin color and thickness is a built-in protection for the skin to UV exposure. Dark, thick skin absorbs most all of the UV before it penetrates the top layer of skin and does not reach the layers producing D3. This has been shown to be as dramatic as a 3-5% transmission in an iguana or bearded dragon, vs a 35-50% transmission in a gecko or chameleon.

So my Burmese Stars (from a lattitude of 21° and forest dwelling most active in the evening) with their very light colored skin in their necks and upper limbs, may well be suited to much lower levels of UV exposure for adequate D3 production. While my Galapagos (from islands right on the equator with high sun) with their dense black skin may need much more UVB exposure for adequate production.

So the species of tortoise probably effects the answer to this question much more than previously thought.
 

iAmCentrochelys sulcata

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A closed chamber does not have more UVB because it is closed. However, there can be more scattering into "shaded' areas by reflection, especially depending upon the color of the walls of the enclosure. UVB is light. It is just light with a wavelength shorter than violet light. So, like any other color, the amount in a closed chamber does not increase, but some may be reflected by the walls and then penetrate some shaded areas.

The amount of UVB needed for D3 production is not know. However, it does appear there is very little needed. The process for D3 production in our tortoises is that a the cells of the skin produces a cholesterol called provitamin-D. (@Tom - vitamin D2 is totally different and produced in plants) When exposed to light in the wavelength close to 297nm as a sharp peak, the provitamin-D is very quickly (few seconds or minutes) converted to Previtamin-D3. This all happens in skin cells. This previtamin-D3 is then isomerzed (molecules are rearranged) by heat applied to the skin over several hours. This is the process that takes time and requires heated skin. This isomerzed previtamin-D3 is now D3. That vitamin D3 is then released into the bloodstream where it is take up by a binding protein where it is taken into the liver and converted to calcediol. This is the 25-hydroxy-vitamin D3 that we look for in blood tests to check vitamin D levels. This calcediol is circulated around the body and creates a store of vitamin D for the tortoise. We do know in humans this has a half-life of about 2 weeks, so this store is available for a month or so. Some of the circulating calcediol that makes it way to the kidneys, is there converted to calcetriol. This is the active compound that controls the calcium levels and metabolism in the body. Calcediol is also taken up by the cells in many major organs and converted there to calcetriol which is instrumental in controlling organ function.

This does not mean we can then assume UVB is only needed for a very short period of time. The built in process that prevents overproduction of D3 in the skin is also UVB dependent. The process for isomerzing previtamin-D3 into D3 - which takes a long time in heated skin, also allows for the breakdown of excess previtamin-D3 with UVB exposure. So this protection mechanism happens with UVB exposure as well.

We do know in humans and mammals, that D3 That is not converted by the liver to calcitriol is then taken up by fat cells to be stored. However, it has not been shown that this happens in reptiles. Reptiles have a different energy store mechanism than fat reserves - using glycogen stores. So we do not know if there are fat stores of D3 in reptiles.
Thanks mark!
 

haydog_99

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just got mine and learned that my MVB bulb is not putting out as much UV light as it should be. I suggest that everyone with a tortoise have one of these.
 

Tom

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A closed chamber does not have more UVB because it is closed. However, there can be more scattering into "shaded' areas by reflection, especially depending upon the color of the walls of the enclosure. UVB is light. It is just light with a wavelength shorter than violet light. So, like any other color, the amount in a closed chamber does not increase, but some may be reflected by the walls and then penetrate some shaded areas.

The amount of UVB needed for D3 production is not know. However, it does appear there is very little needed. The process for D3 production in our tortoises is that a the cells of the skin produces a cholesterol called provitamin-D. (@Tom - vitamin D2 is totally different and produced in plants) When exposed to light in the wavelength close to 297nm as a sharp peak, the provitamin-D is very quickly (few seconds or minutes) converted to Previtamin-D3. This all happens in skin cells. This previtamin-D3 is then isomerzed (molecules are rearranged) by heat applied to the skin over several hours. This is the process that takes time and requires heated skin. This isomerzed previtamin-D3 is now D3. That vitamin D3 is then released into the bloodstream where it is take up by a binding protein where it is taken into the liver and converted to calcediol. This is the 25-hydroxy-vitamin D3 that we look for in blood tests to check vitamin D levels. This calcediol is circulated around the body and creates a store of vitamin D for the tortoise. We do know in humans this has a half-life of about 2 weeks, so this store is available for a month or so. Some of the circulating calcediol that makes it way to the kidneys, is there converted to calcetriol. This is the active compound that controls the calcium levels and metabolism in the body. Calcediol is also taken up by the cells in many major organs and converted there to calcetriol which is instrumental in controlling organ function.

This does not mean we can then assume UVB is only needed for a very short period of time. The built in process that prevents overproduction of D3 in the skin is also UVB dependent. The process for isomerzing previtamin-D3 into D3 - which takes a long time in heated skin, also allows for the breakdown of excess previtamin-D3 with UVB exposure. So this protection mechanism happens with UVB exposure as well.

We do know in humans and mammals, that D3 That is not converted by the liver to calcitriol is then taken up by fat cells to be stored. However, it has not been shown that this happens in reptiles. Reptiles have a different energy store mechanism than fat reserves - using glycogen stores. So we do not know if there are fat stores of D3 in reptiles.
Way wayyyyy better answer than mine. :)

Thanks as always for making all of us smarter Mark.
 

Tom

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just got mine and learned that my MVB bulb is not putting out as much UV light as it should be. I suggest that everyone with a tortoise have one of these.
I agree. At the very least, anyone who wants to use indoor UV should have one. Some people live in warm climates and their adult tortoises live outside full time. I don't think those people "need" one, but they are still fun and useful.
 

Tom

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@Markw84 What are your thoughts on the OP's numbers? @CandyAss is getting a UVI of 2.9 over a desert tort. Do you feel this is adequate? Too much? All day, or just mid day?
 

Cleopatra 2020

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So glad you like it. I mess with mine frequently just checking to see what outdoor UV levels are doing at different times of the day, with or without cloud cover, different seasons, etc...

There is much debate about what intensity of UV is needed and how long they need to be exposed to it. There are many variables to consider. I think a level of 2.9 all day will be more than sufficient to meet any tortoises UV needs. In your excellent climate, they should be getting sunshine on a regular basis for most of every year. This being the case, you probably don't need indoor UV at all. Add a calcium supplement with D3 twice a week, and some occasional Mazrui, and your tortoise will never get MDB.
I cut Rosie's uv down to 1.5 - 2 hrs a day evenly between a.m. and p.m. and the other 10 hrs led lighting.. with her br30 flood for basking and ambient heat
 
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CandyAss

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I would think the 2.9 UVI is good for all day. Most basking would normally be done morning and evening for a desert tortoise, not midday. So midday levels are not what I would duplicate.
The UV index in and around the Mojave Desert is insane. Yesterday at 9am the UVI in Mojave, Ca, which is on the western edge of the Mojave Desert was already at 7.0. No wonder desert torts are in their burrows most of the time!
 

Viola B

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A closed chamber does not have more UVB because it is closed. However, there can be more scattering into "shaded' areas by reflection, especially depending upon the color of the walls of the enclosure. UVB is light. It is just light with a wavelength shorter than violet light. So, like any other color, the amount in a closed chamber does not increase, but some may be reflected by the walls and then penetrate some shaded areas.

The amount of UVB needed for D3 production is not know. However, it does appear there is very little needed. The process for D3 production in our tortoises is that a the cells of the skin produces a cholesterol called provitamin-D. (@Tom - vitamin D2 is totally different and produced in plants) When exposed to light in the wavelength close to 297nm as a sharp peak, the provitamin-D is very quickly (few seconds or minutes) converted to Previtamin-D3. This all happens in skin cells. This previtamin-D3 is then isomerzed (molecules are rearranged) by heat applied to the skin over several hours. This is the process that takes time and requires heated skin. This isomerzed previtamin-D3 is now D3. That vitamin D3 is then released into the bloodstream where it is take up by a binding protein where it is taken into the liver and converted to calcediol. This is the 25-hydroxy-vitamin D3 that we look for in blood tests to check vitamin D levels. This calcediol is circulated around the body and creates a store of vitamin D for the tortoise. We do know in humans this has a half-life of about 2 weeks, so this store is available for a month or so. Some of the circulating calcediol that makes it way to the kidneys, is there converted to calcetriol. This is the active compound that controls the calcium levels and metabolism in the body. Calcediol is also taken up by the cells in many major organs and converted there to calcetriol which is instrumental in controlling organ function.

This does not mean we can then assume UVB is only needed for a very short period of time. The built in process that prevents overproduction of D3 in the skin is also UVB dependent. The process for isomerzing previtamin-D3 into D3 - which takes a long time in heated skin, also allows for the breakdown of excess previtamin-D3 with UVB exposure. So this protection mechanism happens with UVB exposure as well.

We do know in humans and mammals, that D3 That is not converted by the liver to calcitriol is then taken up by fat cells to be stored. However, it has not been shown that this happens in reptiles. Reptiles have a different energy store mechanism than fat reserves - using glycogen stores. So we do not know if there are fat stores of D3 in reptiles.
Thank you Mark. We are all learning. It's wonderful!
 
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