# UVB life span



## Raymo2477 (Oct 2, 2016)

Question about the time UVB bulbs last I've heard 6 months, 9 months, a year...which one is it?

I assume those time frames vary based on type (MVB, tube), maker, and time run.

I also assume that the clock is running while they're on so storing over the summer doesn't affect them.

Any input is appreciated.


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## wellington (Oct 2, 2016)

There is no way of telling without a uv meter. They are costly and most don't have them. I use both Mercury and tube florescent. The tube are for my lizards. I go six months on them and a year or a little more on the Mercury. During the summer months the Mercury is off completely. During last winter I used them half the time. This winter I will be using them only about once a week for a 12 hour period so will be taking that into account before replacing.


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## Travis (Oct 11, 2016)

I think a good rule of thumb is every 6 months. I've read that numerous places and it's what I personally always do. But like Wellington said above, only surefire way to know is uv meter. But those are pricey


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## Yvonne G (Oct 11, 2016)

The consensus of opinion is replace the bulb every 6 months.


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## Tom (Oct 11, 2016)

The manufacturers want to sell more bulbs. I have 10.0 tubes that are still producing good UVB after 24 months.

We have a vet here who has been testing MVBs and he says the current iteration only makes UVB for 3 months, even though the bulb still lights up everyday.

Without a meter you are just guessing. You might be throwing away a perfectly good working bulb, or you might be going months with no UV for your indoor tortoise over winter. In addition to ensuring that your tortoise is getting what it needs, the purchase of the meter will also prevent you from wasting money unnecessarily and save you money in the long run. For an animal that will live, and need UV bulbs, for decades, having a UV meter makes sense.

https://www.solarmeter.com/model65.html


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## Yvonne G (Oct 11, 2016)

I guess I'll have to continue the seat-of-the-pants method. That meter is out of my price range!


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## leigti (Oct 11, 2016)

I just consider the meter to be a long-term investment. The tortoise is going to live for a long long time so it's worth it to me.


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## Markw84 (Oct 11, 2016)

I use a 4 foot uvb tubes in my 3 enclosures. They cost about $35 ea. If I went by "seat of the pants" and replaced every 6 months, that would be about $200 per year. Like @Tom I have found my bulbs actually are putting out great UVB at 18 and 24 months. I've saved money by !having the meter, let alone the piece of mind KNOWING the Tortoises are getting the UVB needed.


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## Shaif (Nov 17, 2016)

Tom said:


> The manufacturers want to sell more bulbs. I have 10.0 tubes that are still producing good UVB after 24 months.
> 
> We have a vet here who has been testing MVBs and he says the current iteration only makes UVB for 3 months, even though the bulb still lights up everyday.
> 
> ...




@Tom

Thank you again for the guidance. There is a model of solarmeter (model 6.2) which is cheaper and available on Amazon. The 6.2 measures only uvb. Its mainly marketed for reptiles. I know your link is for the 6.5. This measures uva and uvb. Is there any benefit to buying the 6.5 vs the 6.2? Saves about $50.

Thank you!


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## SarahChelonoidis (Nov 18, 2016)

I'm pro-uv meter as well. Thanks to my 6.5, I know my three foot tubes are still putting out the same UVB that they were 18 months ago (and my meter told me when I had put a dud bulb in too).


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## Markw84 (Nov 18, 2016)

Shaif said:


> @Tom
> 
> Thank you again for the guidance. There is a model of solarmeter (model 6.2) which is cheaper and available on Amazon. The 6.2 measures only uvb. Its mainly marketed for reptiles. I know your link is for the 6.5. This measures uva and uvb. Is there any benefit to buying the 6.5 vs the 6.2? Saves about $50.
> 
> Thank you!


Actually the 6.2 meter is the older model and is a broad range UV meter measuring the whole range of UV approx. 250 - 400 nm. It is great for watching to see when a bulb needs to be replaced and works well. However, its drawback was it could give you the same reading for a bulb that puts out most all of its UV as UVA as it would for one with much more UVB if the TOTAL UV output was the same. It is the UVB we need to monitor to ensure D3 production and we will not be getting that with a reading that looks good, but is mostly from UVA light.

The 6.5 was created to weight the reading very heavily on the 290-315nm range which is the UVB range associated with vitamin D production. So the 6.5 will give you a much more accurate indication of how good the light you are testing is at providing the UVB needed for D3 synthesis.

The 6.5 is the way to go for what we are wanting from the meter.


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## Markw84 (Nov 18, 2016)

Also, Todd at lightyourreptiles.com now sells the solarmeter 6.5 for a bit less than the solarmeter website.


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## Shaif (Nov 18, 2016)

Markw84 said:


> Actually the 6.2 meter is the older model and is a broad range UV meter measuring the whole range of UV approx. 250 - 400 nm. It is great for watching to see when a bulb needs to be replaced and works well. However, its drawback was it could give you the same reading for a bulb that puts out most all of its UV as UVA as it would for one with much more UVB if the TOTAL UV output was the same. It is the UVB we need to monitor to ensure D3 production and we will not be getting that with a reading that looks good, but is mostly from UVA light.
> 
> The 6.5 was created to weight the reading very heavily on the 290-315nm range which is the UVB range associated with vitamin D production. So the 6.5 will give you a much more accurate indication of how good the light you are testing is at providing the UVB needed for D3 synthesis.
> 
> The 6.5 is the way to go for what we are wanting from the meter.





Perfect! Thank you so much. This is exactly what I needed to know. I'll get the 6.5 today.

Much appreciated!


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## Tom (Nov 18, 2016)

Shaif said:


> @Tom
> 
> Thank you again for the guidance. There is a model of solarmeter (model 6.2) which is cheaper and available on Amazon. The 6.2 measures only uvb. Its mainly marketed for reptiles. I know your link is for the 6.5. This measures uva and uvb. Is there any benefit to buying the 6.5 vs the 6.2? Saves about $50.
> 
> Thank you!



The 6.2 works and that is what most people used in years past. Most people switched to the 6.5 model because it more specifically focuses on the part of the lighting spectrum that we are concerned with for our tortoises and D3 production. I have both, but most of the time I just use the 6.5 and use the UV index numbers for reference, instead of the micro watts per sq. cm that you get with the 6.2.

Hope that all made sense. What I'm saying is that I'd spend the extra 50 bucks and get the 6.5.


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## saginawhxc (Nov 18, 2016)

I've been thinking about buying one and threads like this one have pushed me over the edge. As soon as the whole house buying nonsense is over I think this will be my next animal related expenditure. I just want to thank everyone for the great info even though I haven't participated in the discussion.


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## Tidgy's Dad (Nov 18, 2016)

I just replace my MVB every winter. 
I only use it for a few weeks, so also must invest in a meter.
But I'd have to have it shipped and am worried about breakages.


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## Shaif (Nov 19, 2016)

Thank you, friends.

I ordered the 6.5 directly from the the company. Lightyourreptiles.com was out of stock. 

Not cheap, but worth the investment.

Again, your input is so helpful!


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## leigti (Nov 19, 2016)

Tidgy's Dad said:


> I just replace my MVB every winter.
> I only use it for a few weeks, so also must invest in a meter.
> But I'd have to have it shipped and am worried about breakages.


If you don't rely on artificial UVB very much then I wouldn't suggest buying one. I have one because my tortoises are inside for eight months out of the year. It is expensive but I figure it is worth it in the long run for me. Not for everybody but it definitely works for me.


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## Tidgy's Dad (Nov 19, 2016)

leigti said:


> If you don't rely on artificial UVB very much then I wouldn't suggest buying one. I have one because my tortoises are inside for eight months out of the year. It is expensive but I figure it is worth it in the long run for me. Not for everybody but it definitely works for me.


Hi, Tina.
I also use my MVB for a basking spot heat lamp in the cold spells and to give the 14 hours daylight, so it performs a triple function. I know I could just buy a heat lamp, but just in case we have a long, grey cold weather, i use the MVBs to feel safe. More for my benefit than TIdgy's.
I have to have stocks as I cannot buy stuff here, so when i go abroad come back with loads of stuff that I will probably never use.
But it's there, just in case.


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## Shaif (Nov 22, 2016)

Hi All!

I got my 6.5 Solarmeter today. Came in perfect condition from the company. Good, safe packing for those of you who were worried.

I'm using 2 small Megaray 70 watt MVB. They are both about 4 mos old, and produce readings of 4 or so at the substrate level. I use those for heat and uv, and had to try many combinations before I found a way to get my enclosure gradient temps perfect. I get 95deg under the bulbs and upper 70s on the far side. The far side is lit with a HO 5 tube, but it's reading was only 1 on the Solarmeter. That bulb and fixture are only 2-3 weeks old. I'm ok with that being primarily for light.

So far, the megarays are holding up well. But I would not count on the HO 5 uvb tube from reptisun for any real uvb.


If you like, I can keep anyone updated as to how long I can get good output from the Megarays. Keep in mind that mine are the smallest size. They are 15 inches from substrate.


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## Sterant (Nov 22, 2016)

All - The Solarmeter is the way to go, but there is a much less expensive option that has worked well for me. I use it in addition to the Solarmeter 6.5. There is a product called Smart UV Checker. It is a personal UV Index meter for your iPhone. The sensor is a very small unit that plugs into your headphone jack on your phone, then there is a free app you download. You can find these for anywhere between $25 and $35. I have had no problem with it at all. Since I use the same light fixtures on each of my enclosures, I made a rack that holds my phone and hangs on the light fixture in the exact same place every time. This way I can very accurately measure bulbs on a regular basis and monitor the degradation. I would absolutely suggest that everyone use a meter of some type as the bulbs I use (Reptisun 10.0 HO T5) can vary drastically in initial output. I find duds regularly. Here is a link to the Smart UV sensor on Amazon. https://www.amazon.com/dp/B00ZF332XY/?tag=exoticpetnetw-20


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## Shaif (Nov 22, 2016)

Awesome info-- thank you!

Do you guys have a guideline of values to follow?

If reading from the 6.5 solarmeter--

What uv reading is too high?
What uv reading is too low?

Let's assume there is no natural sun (cold winter season).

I have searched and searched and am finding no hard rules or guidelines.

Thank you!


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## Sterant (Nov 22, 2016)

Read this: http://www.uvguide.co.uk/usinguvmeter.htm

In my experience, minuscule changes in the angle of the meter or distance from the bulb makes significant differences in the readout, so comparing your measurement to the measurements of others is tough unless identical fixtures are used wherein the bulb is mounted at a very specific distance and angle from the meter.
The way I use the meter is to measure the initial output of every new bulb, then monitor it over time using a fixture so the meter is in exactly the same position each time. This will let you know if you have a bad bulb, and with good ones, when the UVB output has dropped below a comfortable level.


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## Shaif (Nov 23, 2016)

Thank you, Dan. You are so right-- even small changes make a significant difference. I got a reading of 9.0 below one of my bulbs. I'm worried that that might be too strong. My babies favor that bulb and tend to sit under it for hours.


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## leigti (Nov 24, 2016)

Because my UVB bulbs are on the entire day, 12 to 14 hours, I shoot for a range of 2 to 4 on the solar meter 6.5. All the bulbs i use are long fluorescent high output in high output fixtures. I think Tom Ames for a higher number but he only keeps his UVB lights on for part of the day. @Tom


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## Tom (Nov 24, 2016)

leigti said:


> Because my UVB bulbs are on the entire day, 12 to 14 hours, I shoot for a range of 2 to 4 on the solar meter 6.5. All the bulbs i use are long fluorescent high output in high output fixtures. I think Tom Ames for a higher number but he only keeps his UVB lights on for part of the day. @Tom



I base my educated guesses off of what the sun does here. In mid summer I get readings around 6.0 at mid day. Its only that strong for a few hours, so that is what I simulate indoors. I shoot for a reading around 6 and set those tubes to be on for 3-4 hours a day. This works for me and should be providing more than enough UVB to any tortoise.


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## jaizei (Nov 24, 2016)

Shaif said:


> Awesome info-- thank you!
> 
> Do you guys have a guideline of values to follow?
> 
> ...



http://www.jzar.org/jzar/article/view/150/89


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## Maverick (Nov 24, 2016)

Dan Sterantino said:


> All - The Solarmeter is the way to go, but there is a much less expensive option that has worked well for me. I use it in addition to the Solarmeter 6.5. There is a product called Smart UV Checker. It is a personal UV Index meter for your iPhone. The sensor is a very small unit that plugs into your headphone jack on your phone, then there is a free app you download. You can find these for anywhere between $25 and $35. I have had no problem with it at all. Since I use the same light fixtures on each of my enclosures, I made a rack that holds my phone and hangs on the light fixture in the exact same place every time. This way I can very accurately measure bulbs on a regular basis and monitor the degradation. I would absolutely suggest that everyone use a meter of some type as the bulbs I use (Reptisun 10.0 HO T5) can vary drastically in initial output. I find duds regularly. Here is a link to the Smart UV sensor on Amazon. https://www.amazon.com/dp/B00ZF332XY/?tag=exoticpetnetw-20


Nice find, I'm going see about checking this out...


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## Sterant (Nov 25, 2016)

Shaif said:


> Awesome info-- thank you!
> 
> Do you guys have a guideline of values to follow?
> 
> ...


Like Tom, I shoot for a UVI of 6 on the Solarmeter 6.5 standing it up on the substrate. I leave my lights on for 14 hours a day, but the tortoises can get out of the direct light where the reading is around 1 or 2.


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## Shaif (Nov 25, 2016)

Thank you. I think I still need to tweak my setup. I think the day I get it perfect will be the day my new enclosure arrives. Then the journey begins again!
I thank you for the advice. I've said it many times before: Tortoise people are the best!


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