a brief UVB experiment i did today...

[Jim2109]

for anyone who doubts any of the information in circulation regarding UVB output of flourescent tubes, i have done a small experiment today. its nothing ground breaking or particularly exciting, but my Solarmeter 6.2 UVB meter arrived today and i wanted to give it a try out. the calibration of these units features a test on a precise source of UVB giving 350 uW/cm^2, my meter measured exactly 350 according to the paperwork. so its an accurate one, they can be as much as 10% out either way and still pass quality control by the looks of the sheet. although im sure that is rarely the case.

so i wandered outside, today is a warm but overcast day near not-so-sunny Basingstoke. the sun was highest in the sky, but was covered by light clouds. enough so that i could look directly up at it without having to squint too hard. i took a few UVB readings around the garden, all of them came out at around 132 uW/cm^2. bear in mind that this is a CLOUDY day and not the hottest or most powerful sun that we have experienced recently. id imagine this could be substantially higher on a really hot and sunny day, now that i have my meter i intend to take some more readings on hotter days.

from that i then went to my water dragon vivarium. i am running an Arcadia D3 5% UVB tube. it is 2 months old and mounted with a reflector.

the primary water dragon basking spot, the place where they spend most of their basking time, is around 8" from the bulb. so i positioned my UVB meter here, and took a reading of 20 uW/cm^2.

thats right, TWENTY!! compare that to the 132 that i measured outside on a CLOUDY summers day in England. so out of curiousity i got the tape measure and checked how close i had to put the meter to the bulb to acheive a par reading to my garden. the answer is 2". i had to put the UVB meter 2" from the tube to replicate a cloudy summers day in England. the closest basking spot i provide is just under 3" from the tube, where the output is around 120 uW/cm^2.

consider that the UVB on a typical day in Vietnam or Thailand, both natural dwellings for a CWD, are more like 400-500 uW/cm^2 at their peak and that is rather worrying. it also explains why most lizards are much happier outside in the garden on a sunny day, and why it brings out their colours much more and they are more lively and dont want to go back into their viv!!

ive seen data from the UV Guide on the Megaray bulbs that i am going to be using in my new larger vivarium. the 60W Externally Ballasted version specifically. and at 8" the output is 400 uW/cm^2, at 12" it is around 200 uW/cm^2. the output can be as high as 2000 uW/cm^2 directly in front of the bulb, hence why it is recommended that a minimum distance of 12" is exercised. armed with the correct tool to measure UVB output i may choose to allow the water dragons slightly closer than that though.

there is also test data to suggest that the Megaray bulbs are only 10% down on their initial UVB output after 9 months of use! i think a lot more people should consider using these products and moving away from flourescent tubes. they just dont provide enough UV for sun basking reptiles. even reptiles that arent necessarily considered sun dwellers, such as Chinese Water Dragons (typically) will still spend several hours per day basking in areas of very high UVB. if you provide shade and lower UVB basking spots then they can regulate themselves, with a flourescent tube you never give them that option. they have low UVB or none at all, no other choices.

[taraliz]

wow this is really interesting, especially as I have a beardie and basilisk
The beardie has a 5% compact bulb the baskilsks have a tube but with those readingd I am wondering if I coulf get a megaray in both their vivs?
Thansk for that !

How much was the reader and where'd u get it from?

T

[Jim2109]

meter was £125 from Kimbos Reptile World. i personally think its a must-own item for anyone keeping diurnal reps that require UV. you wouldnt own marine fish without checking salt levels and water pH. reptiles should be monitored for temperature, humidity and UVB. its expensive, but it will pay for itself if you can correctly setup and monitor UVB output. you can replace tubes at the correct time without guessing, and you can keep your reptiles from needing costly vets visits when they suffer health issues from a lack of UVB.

[Pendragon]

Originally Posted by Jim2109

for anyone who doubts any of the information in circulation regarding UVB output of flourescent tubes, i have done a small experiment today. its nothing ground breaking or particularly exciting, but my Solarmeter 6.2 UVB meter arrived today and i wanted to give it a try out. the calibration of these units features a test on a precise source of UVB giving 350 uW/cm^2, my meter measured exactly 350 according to the paperwork. so its an accurate one, they can be as much as 10% out either way and still pass quality control by the looks of the sheet. although im sure that is rarely the case.

so i wandered outside, today is a warm but overcast day near not-so-sunny Basingstoke. the sun was highest in the sky, but was covered by light clouds. enough so that i could look directly up at it without having to squint too hard. i took a few UVB readings around the garden, all of them came out at around 132 uW/cm^2. bear in mind that this is a CLOUDY day and not the hottest or most powerful sun that we have experienced recently. id imagine this could be substantially higher on a really hot and sunny day, now that i have my meter i intend to take some more readings on hotter days.

from that i then went to my water dragon vivarium. i am running an Arcadia D3 5% UVB tube. it is 2 months old and mounted with a reflector.

the primary water dragon basking spot, the place where they spend most of their basking time, is around 8" from the bulb. so i positioned my UVB meter here, and took a reading of 20 uW/cm^2.

thats right, TWENTY!! compare that to the 132 that i measured outside on a CLOUDY summers day in England. so out of curiousity i got the tape measure and checked how close i had to put the meter to the bulb to acheive a par reading to my garden. the answer is 2". i had to put the UVB meter 2" from the tube to replicate a cloudy summers day in England. the closest basking spot i provide is just under 3" from the tube, where the output is around 120 uW/cm^2.

consider that the UVB on a typical day in Vietnam or Thailand, both natural dwellings for a CWD, are more like 400-500 uW/cm^2 at their peak and that is rather worrying. it also explains why most lizards are much happier outside in the garden on a sunny day, and why it brings out their colours much more and they are more lively and dont want to go back into their viv!!

ive seen data from the UV Guide on the Megaray bulbs that i am going to be using in my new larger vivarium. the 60W Externally Ballasted version specifically. and at 8" the output is 400 uW/cm^2, at 12" it is around 200 uW/cm^2. the output can be as high as 2000 uW/cm^2 directly in front of the bulb, hence why it is recommended that a minimum distance of 12" is exercised. armed with the correct tool to measure UVB output i may choose to allow the water dragons slightly closer than that though.

there is also test data to suggest that the Megaray bulbs are only 10% down on their initial UVB output after 9 months of use! i think a lot more people should consider using these products and moving away from flourescent tubes. they just dont provide enough UV for sun basking reptiles. even reptiles that arent necessarily considered sun dwellers, such as Chinese Water Dragons (typically) will still spend several hours per day basking in areas of very high UVB. if you provide shade and lower UVB basking spots then they can regulate themselves, with a flourescent tube you never give them that option. they have low UVB or none at all, no other choices.

You and your experiments Jim

And to add insult to injury, you got your meter befor me, I orded mine in the middle of June, and still waiting

You've hit a very big nail, with a very big hammer, square on the head here, Although I stress to people on here time and time again, to let there beardies get so close to a 10% reptisun tube that they can touch it, you will get people posting, "well 8"~12" is fine mate" .

The uv guide websit is there for all to read, in my view it should be compulsary for anyone buying any animal to have a clear understanding of the uv levels of the animals nutural environment, and then explain to the pet shop owner, (pet shop owners, who am I kidding, what do they know ), exactly how they are going to meet this requirment for the animal they are about to buy.

Just my humble opionion of course

Jay

[Pendragon]

By the way Jim, didn't you mean the 70watt EB metal halide, the 60watt is the old one.

Jay

[bladeblaster]

I may be talking rubbish here, but surely in the wild they would spend a lot of their time out of direct sunlight, where as in a viv they are pretty much in the UV light all the time, meaning that the output has to be massively lower so as not to over expose them?

[moonstruck]

wow... i'm genuinly in shock about the quite frankly s**t output on the D3 bulb! was that a SUPPOSED 12% bulb which is meant to give the output needed for longer than a normal 10%??

I think I know what i'll be buying come pay day

That's really shocking to say the least

[Jim2109]

Originally Posted by jabba1967

And to add insult to injury, you got your meter befor me, I orded mine in the middle of June, and still waiting

You've hit a very big nail, with a very big hammer, square on the head here, Although I stress to people on here time and time again, to let there beardies get so close to a 10% reptisun tube that they can touch it, you will get people posting, "well 8"~12" is fine mate"

i ordered mine at the end of May lol. there was a stock shortage and Darren took delivery of some yesterday. so yours might be on its way shortly.

Originally Posted by jabba1967

By the way Jim, didn't you mean the 70watt EB metal halide, the 60watt is the old one.

i still prefer the looks of the 60W EB. would be interesting if you could make a "map" of the UVB output, in the same way that UV Guide does it. their review of the metal halide looked like the bulbs can be quite inconsistent and the output didnt look as strong as the older 60W non-halide.

Originally Posted by bladeblaster

I may be talking rubbish here, but surely in the wild they would spend a lot of their time out of direct sunlight, where as in a viv they are pretty much in the UV light all the time, meaning that the output has to be massively lower so as not to over expose them?

this is why you must provide areas out of the UV. in something like a Beardie viv this is harder than in a rainforest viv. but in the wild its not like there are areas of selective sunlight. in the desert if they want to get out of the sun theyll hide under a rock. this is easily implemented into a vivarium and is more natural than simply offering a low output UVB source so that they can sit under it all day. ultimately they still wont take on the correct amount of UV.

Originally Posted by moonstruck

wow... i'm genuinly in shock about the quite frankly s**t output on the D3 bulb! was that a SUPPOSED 12% bulb which is meant to give the output needed for longer than a normal 10%??

I think I know what i'll be buying come pay day

That's really shocking to say the least

it was only a 5% D3 bulb, not the 12% one. id imagine that the 12% one will be better, but its not going to be by much more than double, if that. its still nowhere near enough. none of the tubes on the market are.

[Pendragon]

Originally Posted by bladeblaster

I may be talking rubbish here, but surely in the wild they would spend a lot of their time out of direct sunlight, where as in a viv they are pretty much in the UV light all the time, meaning that the output has to be massively lower so as not to over expose them?

Nope, you're not talking rubbish, this is why you have to setup your animals viv properly, you need to allow your animal to make up it's own mind on what it needs.

check out these two picks of my viv, you will see him in full uv basking, and full uv hiding;






The trick is give the animal the choice, this is where the MIN size of the viv becomes important, too small a viv, and you have too many compromises.

Jay

Originally Posted by moonstruck

wow... i'm genuinly in shock about the quite frankly s**t output on the D3 bulb! was that a SUPPOSED 12% bulb which is meant to give the output needed for longer than a normal 10%??

I think I know what i'll be buying come pay day

That's really shocking to say the least

It was the 5%, jim was on about, the 12% is fine

Jay

[Pendragon]

Originally Posted by Jim2109

i still prefer the looks of the 60W EB. would be interesting if you could make a "map" of the UVB output, in the same way that UV Guide does it. their review of the metal halide looked like the bulbs can be quite inconsistent and the output didnt look as strong as the older 60W non-halide.

I must have missed something, I will go back and check on what I have read on all these bulbs, but if my memory is correct, ALL mercury vapour/metal halide lamps can have huge fluctuations in uvb output, this is why you have to have a 6.2 uv meter to test each lamp, this is also why there is NO safe recomended distance.

Did you read these reports on the 70watt metal halide, again I am going to go through it again, but the output of the NEW 70watt is far greater than the 60watt, it is more consistant, and last a hell of a lot longer.

There are reports of the M.V.B uvb output only lasting for 4 months and at £70 a bulb

ReptileUV Mega-Ray Mercury Vapour Lamps for Reptiles - Test Report UV Guide 2006

http://www.reptileuv.com/docs/MegaRa...desOct2008.pdf

Don't forget, these are results of the PROTOTYPE bulbs, the latest batch are spot on, and to give you farther endorsment, Durrell wildlife trust have orded 200 of the 70watt lamps

Jay