Please ad anything you know about "coiled compact florescent bulbs".

[sibi]

Sibi: yes. That was a part of my original post on this and why I thought it more worthy of discussion. There were cases of eye problems with some long tubes though not at all as common but now there are even stronger high output long tubes plus metal halide. That's why I think it's good to keep this discussion going and exploring all possible contributions to the problem

Interesting! I have read all your posts, and you really have a way of explaining the various factors with the use of different bulbs. I enjoy your posts. Can you send me the list of various questions you posted by email? I'd like to answer those questions for future reference. My email is [email protected]

 

[Markw84]

Will do Tommorrow though. I'm done tonight!!!

 

[Turtlepete]

Pete, I love conversing with you, so don't take this as an attack of any kind. Just discussing the matter in a civil tone here, and enjoying the discussion.

I think this is seen more with sulcatas simply because there are more sulcatas out there in the world than any other species. Another contributing factor is that since sulcatas are cheaper, the people who buy them, might be more inclined to buy cheaper lighting and UV options.

Also, I think you may be suffering from a logical fallacy that many people succumb to about sulcatas. Yes sulcatas come from a hot sunny place, but they spend 95-98% of their lives underground and out of the sun. It is very likely, given this fact that your RFs see more sun in the wild than a wild sulcata would, albeit dappled sun...

I'd be rather disappointed in myself if I treated someone disagreeing with me as an offense. The only thing that would offend me is if someone thought they needed to treat me with needless sensitivity as if offending me would be the worst thing in the world (far too common in society).

I understand sulcatas spend a lot of time underground, but 95-98% seems way beyond what I've heard? I was under the impression they spent an enormous amount of time grazing during the "wet season", something also used to validate and support the theory of raising them in humid environments. Yes? Assuming this I'd wager they experience more UV exposure, but that is admittedly a loose guess. As I said, my experience is limited in the area. To me it seems odd that a tortoise from Africa would experience less UV exposure, but perhaps I am wrong.

Tom, on the topic you mention about these bulbs being bad….that is due to a manufacturing error, right? Now heres something to think about….Are not ALL UV bulbs perhaps prone to these manufacturing errors? Any and ALL of these bulbs are manufactured by humans, and humans make errors. I see no reason to assume that absolutely ANY brand is safe from these same kinds of errors! Is it perhaps more common with these bulbs? Maybe. I haven't seen enough information to be confident about that. But keep in mind that these issues could appear with ANY UV bulbs being used. Perhaps not in the same way; there is a possibility of a manufacturing error leading to the bulbs overheating, or blinding them with harsh brightness. The bottom line is that I don't see any reason to assume the same kind of defects couldn't occur in the suggested $60 MVBs that seem to fail after 2 months of usage.

 

[sibi]

Will do Tommorrow though. I'm done tonight!!!

Thanks! I'm burned out too.Good night.

 

[Tom]

I'd be rather disappointed in myself if I treated someone disagreeing with me as an offense. The only thing that would offend me is if someone thought they needed to treat me with needless sensitivity as if offending me would be the worst thing in the world (far too common in society).

Well you've seen more than one person take offense even when I had good intentions, and I wished to make sure that did not happen here. My mistake is incorrectly equating you with that type of person. My apologies. I should have known to just speak to you like a rational, intelligent adult. I've just had so many run-ins for speaking plain English to the wrong people that I've developed a tendency to attempt to be overly diplomatic even in situations that don't require it.

I understand sulcatas spend a lot of time underground, but 95-98% seems way beyond what I've heard? I was under the impression they spent an enormous amount of time grazing during the "wet season", something also used to validate and support the theory of raising them in humid environments. Yes? Assuming this I'd wager they experience more UV exposure, but that is admittedly a loose guess. As I said, my experience is limited in the area. To me it seems odd that a tortoise from Africa would experience less UV exposure, but perhaps I am wrong.

That is a quote from Bernard Devoux's "The Crying Tortoise". Seems like a high percentage to me too, but every minute that Bernard spent in "sucata land" is one more minute than I've spent there. Note to all, not just Pete: The way our sulcatas behave and go about their daily life here in temperate North America is reportedly VERY different than how they spend their days over there. People who have studied them in the wild and don't know them from captive North American sources, are genuinely surprised at how much time they spend above ground here, so says Tomas Diagne.

Tom, on the topic you mention about these bulbs being bad….that is due to a manufacturing error, right?

Wrong. Well... maybe...

We don't know exactly what the problem is. I've never heard the theory that it is a manufacturing error, but it could be. I've heard that its microscopic cracks that form in the phosphor coating during shipping that allow the emission of UVC, but that has not been demonstrated or proven either. Seems plausible, but...

And that brings us back to first hand experience and anecdotal info. I know that those other types of bulbs you mentioned could have some sort of manufacturing defect, BUT they don't. Never seen one case. The coil bulbs, by contrast, frequently, but not always, cause problems. I don't know if its a manufacturing defect, a shipping issue, a design issue, a mis-use issue, all of the above, or some combination of the above and other factors... I just know that lots of reptiles of many species get their eyes burned under those bulbs, and they don't get burned eyeballs under long tubes or MVBs.

 

[Turtlepete]

That is a quote from Bernard Devoux's "The Crying Tortoise". Seems like a high percentage to me too, but every minute that Bernard spent in "sucata land" is one more minute than I've spent there. Note to all, not just Pete: The way our sulcatas behave and go about their daily life here in temperate North America is reportedly VERY different than how they spend their days over there. People who have studied them in the wild and don't know them from captive North American sources, are genuinely surprised at how much time they spend above ground here, so says Tomas Diagne.

Wrong. Well... maybe...

We don't know exactly what the problem is. I've never heard the theory that it is a manufacturing error, but it could be. I've heard that its microscopic cracks that form in the phosphor coating during shipping that allow the emission of UVC, but that has not been demonstrated or proven either. Seems plausible, but...

And that brings us back to first hand experience and anecdotal info. I know that those other types of bulbs you mentioned could have some sort of manufacturing defect, BUT they don't. Never seen one case. The coil bulbs, by contrast, frequently, but not always, cause problems. I don't know if its a manufacturing defect, a shipping issue, a design issue, a mis-use issue, all of the above, or some combination of the above and other factors... I just know that lots of reptiles of many species get their eyes burned under those bulbs, and they don't get burned eyeballs under long tubes or MVBs.

Interesting. I had heard they spent a lot of time above ground during the "wet season". I do agree that its definitely worth mentioning how vastly our tortoises behavior varies from that of their wild counterparts. Some species might never bask in the wild but regularly enjoy doing so in captivity. My forstenii and carbonaria are two such examples for me.

I was sure it was mentioned on the forum at one time about a manufacturing defect causing it…? Could be wrong I suppose. I thought the person had conversed with ZooMed on the issue and they had confirmed its a manufacturing issue. My memory admittedly sucks and perhaps I'm thinking of something totally different? Regardless, I still think its worth mentioning that these same problems could arise with the use of any bulbs. Shoot, any products we use. Malfunctioning heaters have killed a whole lot of reptile collections.
Now, perhaps its more common with these. Once again, I haven't seen enough information to really see it one way or the other. Maybe these problems have been seen more with coil bulbs because coil bulbs were being used more frequently by keepers at the time? Being the cheaper of the options available, it seems like it would've been the natural choice for a lot of keepers. If more keepers were using them, it's plausible to suggest that this is why these issues were observed more often with the use of those bulbs.

Regardless of it all, I'm thankful I live in Florida where my animals can rely on natural sunlight 11 months out of the year. No bulb on the market can rival the benefits of natural sunlight. Not just physiologically, but psychologically as well.

 

[Tom]

Regardless of it all, I'm thankful I live in Florida where my animals can rely on natural sunlight 11 months out of the year. No bulb on the market can rival the benefits of natural sunlight. Not just physiologically, but psychologically as well.

On this we agree 100% Same here. I don't need artificial UV here at all.

My interest on the subject stems from my desire to stop seeing so many cases of burned reptile eyeballs.

 

[Turtlepete]

On this we agree 100% Same here. I don't need artificial UV here at all.

My interest on the subject stems from my desire to stop seeing so many cases of burned reptile eyeballs.

Something worth mention….what about d3? I know this is a little off topic but…

Mainly, members here seem opposed to supplementing with vitamin d3. I've heard from the vets all the horror stories of over-supplenetation, and it's certain something to keep in mind. HOWEVER, I have always believed that in this field, first-hand experience trumps whatever we read in a book. I believe it was Tim (he keeps spiders, can't remember his name on the forum) who keeps is spider tortoises with no UV lights and simply supplements with d3. I wish I could find the forum post where he discussed it. His animals, of course, looked great, and if he was able to reproduce such a difficult species then he was certainly doing something right. I remember reading his forum posts about only supplementing d3 as opposed to using artificial UV lighting, and I was fascinated by it.

I wonder about controlled vitamin d3 supplementation as opposed to UV lights. If we could eliminate their usage entirely, then we eliminate the chance of harming our parts.

Now, I am not at all suggesting this. I'd just like to see the conversation take place. Personally, I have always been opposed to the idea of dietary supplementation as opposed to allowing reptiles to rely on the built-in chemical process to metabolize d3 (however that works….some sort of chemical in the skin that helps them to metabolize d3?) But if it could be done successfully, with controlled doses, it would be interesting how that would affect this conversation. No more bulbs means no more burned eyes.

Just a thought.

 

[DutchieAmanda]

I don't use a coil bulb because of all the stories I read on them. Finally, I chose a MVB for my redfoot because to me it seems most 'natural': combining heat, light and UV in one source. But there's no science there

I did however look into dietary supplementation of vit D3, but in mammals, recently. Vit D is fat soluble, and therefore harder to excrete via urine. It is also toxic in higher doses. Too much UV won't result in toxic doses of vit D because the body regulates the production. Dietary supplementation can relatively easily lead to toxicity. In mammals, only a 4 times higher supplementation than requirement can cause disease. And because I have no idea of the exact requirements and of the actual intake of the supplements in my tort, I wouldn't recommend this.

I had recently had a discussion with one of you on vit D concentrations in natural food sources for redfoots. Vit D is mainly present in fatty foods such as fatty fish and liver. I seldomly feed that to my tort.

In short: I'll stick with my MVB. For me it works in my closed chamber, my redfoot loves to bask (yes, the temps are correct) and I don't see any (eye) problems.

 

[Anyfoot]

Something worth mention….what about d3? I know this is a little off topic but…

Mainly, members here seem opposed to supplementing with vitamin d3. I've heard from the vets all the horror stories of over-supplenetation, and it's certain something to keep in mind. HOWEVER, I have always believed that in this field, first-hand experience trumps whatever we read in a book. I believe it was Tim (he keeps spiders, can't remember his name on the forum) who keeps is spider tortoises with no UV lights and simply supplements with d3. I wish I could find the forum post where he discussed it. His animals, of course, looked great, and if he was able to reproduce such a difficult species then he was certainly doing something right. I remember reading his forum posts about only supplementing d3 as opposed to using artificial UV lighting, and I was fascinated by it.

I wonder about controlled vitamin d3 supplementation as opposed to UV lights. If we could eliminate their usage entirely, then we eliminate the chance of harming our parts.

Now, I am not at all suggesting this. I'd just like to see the conversation take place. Personally, I have always been opposed to the idea of dietary supplementation as opposed to allowing reptiles to rely on the built-in chemical process to metabolize d3 (however that works….some sort of chemical in the skin that helps them to metabolize d3?) But if it could be done successfully, with controlled doses, it would be interesting how that would affect this conversation. No more bulbs means no more burned eyes.

Just a thought.

Don't want take this thread off topic, so short and sweet.

Hi Turtlepete.

I've been looking into vitamin D(D2 and D3) sources.

D2 come from fungus, if mushrooms are left in the sun for an hour before feeding the vitamin D level increases, mushrooms absorb the D2 just like our skin I believe.

D3 comes from uvb rays, fleshy fish, egg yolk and liver.

I was trying to work out how my hingebacks a forest tort get their vitamin D in order to absorb calcium. Is it plants? I came across Terry(redfootnerd) a couple of weeks ago to find he believes D3 is from mainly the diet .

So I started to look into this, and found this study. Please could you and any others have a read and let me know your thoughts. I can't link it in because the link is a direct download. Do a google search for 'PHD vitamin D in plants', it should be the first thing to come up.

Whilst reading the part about grass containing Vit D I was thinking of Tom and his herd of sullies, today I learnt that sullies spend most part of their life in a burrow. Is the short period of time in the sun enough for the Vit D needs, I don't know.

If you read this study, then after do a search on edible plants from the solanaceae family. Quite a few come from South America(and other countries)

Thought you may find it an interesting read.

Another question I ask myself and can't find an answer to. Are worms a source of D3. Moles spend most part of their life underground. Where does the Vit D come from to aid correct bone growth.

Maybe something or nothing. Need more brains on the subject.

 

[Redfoot NERD]

WELLLL... we've heard everything from irrational emotional outbursts and attacks of others to totally technical scientific analysis .. but where is the actual explanation of how these devices are applied that produce these claimed horrific results???

How is it that some have years of no ill effects and others have almost immediate [ claimed ] blindness etc.?

Can we please get detailed set-ups??? - NOT ".. because I went by the instructions and it blinded my tortoises!!!!." - that's not a legitimate explanation.. that's a claimed reaction. I'm asking for the "action" that creates the "reaction" PLEASE???

I am under the impression that this topic/thread is to find out what we know about
"coiled compact florescent bulbs".
We've heard the "what" and the "why" and the "when"! Can we hear the specific "how" ( pics would be helpful ) --- it has been requested a number of times!

 

[sibi]

WELLLL... we've heard everything from irrational emotional outbursts and attacks of others to totally technical scientific analysis .. but where is the actual explanation of how these devices are applied that produce these claimed horrific results???

How is it that some have years of no ill effects and others have almost immediate [ claimed ] blindness etc.?

Can we please get detailed set-ups??? - NOT ".. because I went by the instructions and it blinded my tortoises!!!!." - that's not a legitimate explanation.. that's a claimed reaction. I'm asking for the "action" that creates the "reaction" PLEASE???

I am under the impression that this topic/thread is to find out what we know about
"coiled compact florescent bulbs".
We've heard the "what" and the "why" and the "when"! Can we hear the specific "how" ( pics would be helpful ) --- it has been requested a number of times!

I,,for one, can't provide pics of the eye irritation and swelling cause I wasn't even a member then. It was when my torts started to get sick that I sort help at the forum. I didn't know to take pics of their condition, the messed up bulb, or their habitat. I suspect that many were in the same position I was in, and didn't take pics. However, this doesn't negate that the problem with the coil bulb was real. What's offensive here is that you are implying we are liars, or don't know what we're talking about. You're like the doctor that refused to listen to the patient. The patient reveals the symptoms and tells the doctor what she thinks is going on. The doctor dismisses her concerns, because he has more knowledge than she does, and in doing so, misses the obvious. In reality, I can't tell you how many times that happens.
Perhaps, there are some who can provide pics, information about the bulb, their setup, etc. but, that's not going to satisfy you. Why don't you just give it up? You're not going to prove or convinced anyone because what's really needed hasn't been done, nor do I see a through investigation of the bulb being conducted over a series of species and conditions anytime soon.

 

[DutchieAmanda]

No need to scream Redfoot Nerd

I just stumbled upon a really interesting scientific article on UV lights: The UV-tool, a guide to the selection of UV lighting for reptiles and amphibians in captivity
They have measured UV output of different types of lights and also assessed the needs of many reptiles, including many tortoises and turtles. The didn't find the bad <290 nm wavelengths in any of the bulbs in the test. Interesting reading material!

 

[Markw84]

To me this is exactly on topic. All these issues are interrelated. The issue of this discussion, I believe, is - How to we properly provide artificial levels of UVB where well being and vitamin D3 is produced, yet no harm is done. Or, supplement with vitamins, yet I believe UVA certainly and probably UVB is still very beneficial to tortoise well being. The sources we have now are fluorescent and MVB. MVB is very hot, and very bright - so those are considerations. That leaves Fluorescent. Both tube and compact have shown problems in the past, and some manufacturing methods were changed as they used to emit too much UVC with some phosphor combinations. That seems to have slowed down the initial issues that created such a furor. However, it seems some still experience issues that could be the result of damaged bulbs, (not manufacturing errors) - in particular compact ones. I don't know how they are technically made and the phosphor applied, but I could theorize how it would seem more plausible with the thinner tubes and glass bent in coils or loops, the phosphor may be more subject to a possible displacement and damage in a compact. It is the type of phosphor and type of glass used that filters the wavelength the vaporized mercury emits in a fluorescent (and MVB). But - is this the case? Are we really dealing with a bad bulb now damaged to where it emits UVC with these newer bulbs? Or are we automatically immediately pointing to that as the cause because of those past issues, and not seeing the issues we will still be left with - because UVB will always be potentially damaging to cells when overexposed, and the limiting triggers tortoises have developed to monitor their basking is altered in an artificial environment with a non-natural, very different light source of any kind. I don't know the answer to that question. Hence my willingness to stick my neck out and risk being misunderstood in an effort to explore this!

So what is best for our tortoises?

SHOULD WE SUPPLEMENT?

Every study I can find, finds herbivorous reptiles cannot get anywhere near enough D3 from their food. It can be supplemented, but that does lead to the issue of overdose, which is not good at all. Overdose rapidly develops kidney failure, hardening of some organs, and death. So in our efforts to ensure especially our hatchlings get their D3 (so they can absorb calcium and harden their bones and shells) some that we see and assume as hatchling failure syndrome, could very actually be vitamin d overdose! New tortoise owners often start with a hatchling and see the softer shells and hear they need calcium and D3. More would be better since my hatchling's shell is not hard and I want to help it best I can - may sometimes be assumed.

WHY WOULD PROVIDING UVB BE BETTER?

So reptiles are designed to manufacture d3 from sunlight. In particular UVB. UVB in a particular wavelength that is very close to the UVC wavelengths! They cannot overdose this - as the skin synthesizes provitaminD, which is rapidly converted to previtaminD and with heat added over time, that is then converted to D3. D3 is then absorbed into the blood stream, but as UVB also breaks down D3, that which isn't absorbed is broken down. So basking self-regulates the proper amounts of D3.

Additionally, and often overlooked, all these lights also provide UVA. The eye anatomy of a tortoise is different than ours. They even have a cone in the eye we do not. Also, he pineal gland is a light sensitive and very UV sensitive organ. Tortoises use UVA and probably UVB for vision, sensing daily and annual cycles, Identifying plants and sexual partners, and we know it also allows even humans to produce beta endorphins necessary for well being and activity levels. Ever noticed the stripes, colors and patterns on aquatic and many tortoise legs and neck? Those look very different to a chelonian with their added UVA vision and they use those as visual cues in identifying a mate of the proper species and sub species. The world of plants looks much different to them under UVA and identifying the right plants to eat by vision as well as smell is key.

WHAT ARE THE BASKING REQUIREMENTS, THEN?

For D3 - They don't need much UVB to accomplish this. Various species have developed different strategies and anatomy. Thicker skin and darker skin dramatically limits UVB penetration. Think of sulcata's thick skin, Galops and Aldabra's very dark skin, and habit to retreat to pools when there is little shade as the water immediately filers any UVB that could reach their legs. I know my Sulcata's also like to flip mud up on themselves whenever they get a chance on a bright day, and I assume they would do this in the wild, along with spending a great amount of their time in a deep burrow. Forest species can obtain the UVB they need from shaded basking and tend to bask in filtered sun and early morning. There is enough reflected UVB in the shade in the tropics to easily allow D3 production.

But what tells a tortoise he's had enough? How do they naturally protect their eyes from the UVB? Their more sensitive areas of their skin? In natural sunlight, no mater how bright, UVA and UVB accounts for much less than 1% of the light intensity. UVC does not exist in nature on earth in sunlight - it is all filtered out by the atmosphere. The UVB alone probably way under 0.1% And the heat generated by sunlight is significant. a 5.0 UV bulb means that 5% of the light intensity is UVB alone - a 10.0 is 10% UVB. Because the total light is so much less intense than sunlight we need that much to provide enough UVB where the tortoise basks - whether trying to simulate open sun, or the reflected natural UVB of a shaded forest. But that means for what the tortoise sees and feels, he is probably getting 100 times more UVB than when he would 'feel' the same with natural light! That seems to open the door for overexposure where other gradients are not provided, or and enclosure too small, lamp too close, etc. I DON"T KNOW! But I would like to find out.

 

[Anyfoot]

To me this is exactly on topic. All these issues are interrelated. The issue of this discussion, I believe, is - How to we properly provide artificial levels of UVB where well being and vitamin D3 is produced, yet no harm is done. Or, supplement with vitamins, yet I believe UVA certainly and probably UVB is still very beneficial to tortoise well being. The sources we have now are fluorescent and MVB. MVB is very hot, and very bright - so those are considerations. That leaves Fluorescent. Both tube and compact have shown problems in the past, and some manufacturing methods were changed as they used to emit too much UVC with some phosphor combinations. That seems to have slowed down the initial issues that created such a furor. However, it seems some still experience issues that could be the result of damaged bulbs, (not manufacturing errors) - in particular compact ones. I don't know how they are technically made and the phosphor applied, but I could theorize how it would seem more plausible with the thinner tubes and glass bent in coils or loops, the phosphor may be more subject to a possible displacement and damage in a compact. It is the type of phosphor and type of glass used that filters the wavelength the vaporized mercury emits in a fluorescent (and MVB). But - is this the case? Are we really dealing with a bad bulb now damaged to where it emits UVC with these newer bulbs? Or are we automatically immediately pointing to that as the cause because of those past issues, and not seeing the issues we will still be left with - because UVB will always be potentially damaging to cells when overexposed, and the limiting triggers tortoises have developed to monitor their basking is altered in an artificial environment with a non-natural, very different light source of any kind. I don't know the answer to that question. Hence my willingness to stick my neck out and risk being misunderstood in an effort to explore this!

So what is best for our tortoises?

SHOULD WE SUPPLEMENT?

Every study I can find, finds herbivorous reptiles cannot get anywhere near enough D3 from their food. It can be supplemented, but that does lead to the issue of overdose, which is not good at all. Overdose rapidly develops kidney failure, hardening of some organs, and death. So in our efforts to ensure especially our hatchlings get their D3 (so they can absorb calcium and harden their bones and shells) some that we see and assume as hatchling failure syndrome, could very actually be vitamin d overdose! New tortoise owners often start with a hatchling and see the softer shells and hear they need calcium and D3. More would be better since my hatchling's shell is not hard and I want to help it best I can - may sometimes be assumed.

WHY WOULD PROVIDING UVB BE BETTER?

So reptiles are designed to manufacture d3 from sunlight. In particular UVB. UVB in a particular wavelength that is very close to the UVC wavelengths! They cannot overdose this - as the skin synthesizes provitaminD, which is rapidly converted to previtaminD and with heat added over time, that is then converted to D3. D3 is then absorbed into the blood stream, but as UVB also breaks down D3, that which isn't absorbed is broken down. So basking self-regulates the proper amounts of D3.

Additionally, and often overlooked, all these lights also provide UVA. The eye anatomy of a tortoise is different than ours. They even have a cone in the eye we do not. Also, he pineal gland is a light sensitive and very UV sensitive organ. Tortoises use UVA and probably UVB for vision, sensing daily and annual cycles, Identifying plants and sexual partners, and we know it also allows even humans to produce beta endorphins necessary for well being and activity levels. Ever noticed the stripes, colors and patterns on aquatic and many tortoise legs and neck? Those look very different to a chelonian with their added UVA vision and they use those as visual cues in identifying a mate of the proper species and sub species. The world of plants looks much different to them under UVA and identifying the right plants to eat by vision as well as smell is key.

WHAT ARE THE BASKING REQUIREMENTS, THEN?

For D3 - They don't need much UVB to accomplish this. Various species have developed different strategies and anatomy. Thicker skin and darker skin dramatically limits UVB penetration. Think of sulcata's thick skin, Galops and Aldabra's very dark skin, and habit to retreat to pools when there is little shade as the water immediately filers any UVB that could reach their legs. I know my Sulcata's also like to flip mud up on themselves whenever they get a chance on a bright day, and I assume they would do this in the wild, along with spending a great amount of their time in a deep burrow. Forest species can obtain the UVB they need from shaded basking and tend to bask in filtered sun and early morning. There is enough reflected UVB in the shade in the tropics to easily allow D3 production.

But what tells a tortoise he's had enough? How do they naturally protect their eyes from the UVB? Their more sensitive areas of their skin? In natural sunlight, no mater how bright, UVA and UVB accounts for much less than 1% of the light intensity. UVC does not exist in nature on earth in sunlight - it is all filtered out by the atmosphere. The UVB alone probably way under 0.1% And the heat generated by sunlight is significant. a 5.0 UV bulb means that 5% of the light intensity is UVB alone - a 10.0 is 10% UVB. Because the total light is so much less intense than sunlight we need that much to provide enough UVB where the tortoise basks - whether trying to simulate open sun, or the reflected natural UVB of a shaded forest. But that means for what the tortoise sees and feels, he is probably getting 100 times more UVB than when he would 'feel' the same with natural light! That seems to open the door for overexposure where other gradients are not provided, or and enclosure too small, lamp too close, etc. I DON"T KNOW! But I would like to find out.

A good read Mark.

So IF a sully does spend 95% of its time in a burrow (where I am assuming there is no uv deflection) is the other 5% of the time in the sun enough for the required amount of d3 intake.
Just thought, 5% of a day is 72 minutes. I'm now thinking yes it would be enough time.

 

[Markw84]

A good read Mark.

So IF a sully does spend 95% of its time in a burrow (where I am assuming there is no uv deflection) is the other 5% of the time in the sun enough for the required amount of d3 intake.
Just thought, 5% of a day is 72 minutes. I'm now thinking yes it would be enough time.

Yes. BUT... here I go again. I just don't see things with this in simple answers.

In bright intense light, it wouldn't take long for UVB to stimulate the formation of provitaminD - previtaminD. That happens very quickly. However, the skin needs to then be heated and over a few hours that is converted to D3. So a lot of various types of basking behavior is also importantly thermoregulation. But from pictures I remember seeing 40 and 50 years ago of sulcata tortoises in the wild and people catching them, and watching my own sulcatas who were allowed to dig burrows, and seeing CA desert tortoises, I can't help believe they also spend some time hiding in the entrance to their burrow waiting to quickly slide back down if disturbed. I know my sulcatas and the CA Desert tortoises do this. This added form of basking would be a way they would get plenty of reflected UVB and added heat.

Also the tortoises body stores this for use. I always seem to end up getting geeky and boring my dear Brenda always says. And this thread proves it to her. So here I go again...
D3 as it is formed in the skin is actually binded to by a protein in the blood where it is carried to the liver and converted to calcediol This, in the bloodstream is carried to the kidneys and calcetriol is created. This is what the body uses to metabolize calcium among other thing. At the calcediol stage, this in mammals at least, has a half life of about 2 weeks in the bloodstream - so is available to the kidneys without the need to bask for some time. This is what good reptile vets will check the level of in blood samples to see how a reptile is doing on vitamin d.

 

[Anyfoot]

Yes. BUT... here I go again. I just don't see things with this in simple answers.

In bright intense light, it wouldn't take long for UVB to stimulate the formation of provitaminD - previtaminD. That happens very quickly. However, the skin needs to then be heated and over a few hours that is converted to D3. So a lot of various types of basking behavior is also importantly thermoregulation. But from pictures I remember seeing 40 and 50 years ago of sulcata tortoises in the wild and people catching them, and watching my own sulcatas who were allowed to dig burrows, and seeing CA desert tortoises, I can't help believe they also spend some time hiding in the entrance to their burrow waiting to quickly slide back down if disturbed. I know my sulcatas and the CA Desert tortoises do this. This added form of basking would be a way they would get plenty of reflected UVB and added heat.

Also the tortoises body stores this for use. I always seem to end up getting geeky and boring my dear Brenda always says. And this thread proves it to her. So here I go again...
D3 as it is formed in the skin is actually binded to by a protein in the blood where it is carried to the liver and converted to calcediol This, in the bloodstream is carried to the kidneys and calcetriol is created. This is what the body uses to metabolize calcium among other thing. At the calcediol stage, this in mammals at least, has a half life of about 2 weeks in the bloodstream - so is available to the kidneys without the need to bask for some time. This is what good reptile vets will check the level of in blood samples to see how a reptile is doing on vitamin d.

The 2 week life period in the blood stream I did not know. I'm going to to let you go again. Your talking about d3 from uvb. What about d3 from oral intake. Im lead to believe this is a much slower process than the uvb absorbed d3.

 

[Markw84]

No long tirade necessary here. It is the same. The D3 get the protein bind in the intestines - enters the bloodstream and all else the same. The difference is that in the skin - the exposure to UVB breaks down excess D3 so no overdose. From previtaminD to D3 takes hours in the skin with heat. But UVB breaks down D3 in the skin so only a controlled amount is absorbed into the bloodstream.

 

[Markw84]

No need to scream Redfoot Nerd

I just stumbled upon a really interesting scientific article on UV lights: The UV-tool, a guide to the selection of UV lighting for reptiles and amphibians in captivity
They have measured UV output of different types of lights and also assessed the needs of many reptiles, including many tortoises and turtles. The didn't find the bad <290 nm wavelengths in any of the bulbs in the test. Interesting reading material!

Yes, this is a great study and lots of useful information here in selecting the right type light. But they did not test any compact fluorescents, and never addresses any potential eye issues, or other related possible problems.

 

[Markw84]

Yes, this is a great study and lots of useful information here in selecting the right type light. But they did not test any compact fluorescents, and never addresses any potential eye issues, or other related possible problems.

I also remember going through this and not really agreeing with many of the habitat classifications they gave to some chelonians. Not sure how they came up with some. But still useful.