Updated: May 30, 2019
Hey guys, how much UVB is enough? How much is too much? What skinks need what? What brands are best? What types are best? Are there dangers and risks to UVB? How do you know you’re providing the correct amount? Find out today in this video.
Welcome to ReptileMountain.TV a channel dedicated to evidence based reptile keeping where opinion is not fact. I’m TC Houston a former professional AZA zookeeper and current skink and reptile breeder dedicated to providing quality information to the global reptile community. If you are new please go ahead and hit that subscribe button and the bell to ensure you don’t miss an upload. If you’ve been here before and haven’t subscribed … get with it y’all?
I want to start by saying there are products on the market for UVB that are fantastic and products that can seriously harm your animals. I'm not talking about those off the wall knock off brands either… I’m talking about mainstream brands. So be sure to watch this whole video because your animal’s health could literally depend in it.
Alright what is UVB what is it not? UV stands for ultraviolet and it refers the the wavelengths of light that are shorter than and just below violet on the spectrum which humans can see.
There are three types of Ultraviolet light A B and C.
For our purposes today were talking about type B which is the specific type that plays a critical role in natural production of vitamin d3 in reptiles.
In really simplified terms our skinks blue tongues, pink tongues, social and crevice skinks and many other reptiles depend on UVB light from the sun to produce vitamin d3 which is a vector/cataylist/mechanism for calcium absorption.
Thus, no d3 no calcium absorption meaning weak bones which leads to loads of problems including but not limited to metabolic bone disease and even death.
Therefore the use of UVB in D3 synthesis is the most natural and primary method by which most omnivorous and herbivorous reptiles obtain most of their vitamin d3 and maintain strong bones and overall health.
What UVB is not. It is not a magical bulb whereby you animal will be transformed into a
breeding, thriving, Olympic gold medal winning creature simply because you turned on a special bulb. UVB will not make up for any lack in other husbandry deficiencies. A crappy diet is still a crappy diet, improper humidity is still improper humidity no matter what light you shed on the problem...you get it...what light...uvb is light ahh okay....
I am not going to discuss whether UVB is “required” for skinks. I will say it is the primary and most natural method of ensuring your animal has d3. However, There is a multitude of evidence to support that blue tongues can live and yes thrive without ever being given UVB. I have a whole video on that here so please check that out and come right back.
Let’s get to addressing those questions we all have. How much is enough? How much is too much? What type do I use? What brand is best? And so on…
There are three commonly available types of UVB bulbs in the industry, yes there are a few others but I’m talking about the main three. The linear bulb the compact fluorescent bulb and the vapor bulbs sometimes call mercury vapor bulbs. So each of these bulbs has specialized components allowing for the mercury in the bulb itself to be charged to a point of producing Ultraviolet B waves. Each bulb type has a specific designed purpose. The linear bulbs are designed to produce a steady even amount of UVB across a broad lighted range. The compact fluorescents can provide localized areas of UVB in stronger but in a more narrow area that often simulates a sun patch coming through the trees. A mercury vapor bulb produces both strong UVB radiation in a more broad area than the compact fluorescents but not as broad as the linear bulbs. Mercury vapors also provide heat so they can serve as a basking heat source and UVB source. Many of the bulbs on the market come self ballasted and work with either a specified fixture or a standard ceramic light fixture.
Within the linear bulbs there are two main types T8 and T5 High output. The T8 bulbs are wider in diameter and produce a less consistent and weaker UVB output than the more narrow T5 bulbs. T8 bulbs are the first kind that was marketed to private keepes and seems to be getting phased out by the newer more powerful T5 bulbs.
As I shared in my Art of Reptile Keeping video (point) the answer to what bulb to use certainly depends on the variables within the species natural behaviors, enclosure type, the environment, and the keepers goals. An example of natural behavior variables would be, my gidgee skinks (Egernia stokesii). Their wild counterparts are often viewed out on rocks, logs, and tree branches in the daytime under the hot Australian sun disappearing at midday but appearing again in the early afternoon. They do well with basking areas that can be as hot as 120F surface temps and do well with UV amounts similar to the bearded dragon. Whereas, an Eastern blue tongue may bask in the open early or in a partially sunlit area for thermoregulation purposes taking in lower levels of UVB than a Gidgee Skink or Bearded Dragon.
An example of enclosure variables would be my son’s Horsfield’s (or russian) Tortoise (testudo horsfieldii) has an open air tortoise tub with a mercury vapor bulb. There is no barrier between the bulb and the tortoise other than air whereas my Berber Skink have a ¼ hardware cloth aka screeen between the bulb and their skin. Anything between the bulb’s surface and the animals skin can affect the amount of UVB absorbed. Many newer bulbs are manufactured to mitigate screen mesh as a barrier but none the less the enclosure and environment affects the type of bulb. The further away from the bulb the animal is the less UV the bulb provides. So a really tall enclosure and a really short enclosure will have different UV reading for the animals even with the same bulb. Also cage furniture can affect the UV waves as well. Even this tape measure affects the waves hitting this Solarmeter. So plant cover and cage decor can impact the UV.
Keeper’s goals also play a role in deciding what bulb to use. An animal that requires high amounts of UV and heat may do best with a Mercury Vapor Bulb if the cage set up allows for the bulb to not over heat the enclosue. For example my Gidgee skinks fall into this category however I keep them in an exoterra large low which is short. The lowest watt mercury vapor bulbs still are too hot for my set up because I need the space above the cage for storange and don’t wish to hang the bulb higher to reduce temps. So I use ceramic heat emitter for heat and a ZooMed T5 High Output linear bulb for UV. The lite area of the cage have a UV gradient range from 2.0-7.0 depending on location within the cage. What wouldn’t work would be a compact florecscent “coil” bulb. They don’t put off a broad enough area for the animals to get a truly quality gradient over a wide enough space like they would in the wild unless I used several bulbs across the top and at that point my cost would be higher to do that than for one linear bulb.
How does one know what to get then? Fantastic question! To answer that let me show you This This is a Solarmeter 6.5 and this is a Solarmeter 6.2r These are UVB meters that can measure the output of UVB coming from bulbs and even the sun. Using these meters. The 6.5 specifically, a team of herpetologists from Texas Christian University led by Dr. Gary Ferguson looked that the UV index uses and behaviors of several species of reptiles to develop what is called the Ferguson Index or Ferguson zones. These are general guidelines for what UV indexes are used by what species or types of animals. So for blue tongue skinks, my bread and butter as you know... thier research says they fall in between zone 2 and zone 3 requiring approximately a 1.1-3.0 UV index for UVB. So taking this Soloarmeter and first measuring where my animal basks and how far from the bulb I can then take a reading that allows me to know if I’m on track for a blue tongue skinks.
How do you know what to get? First Consult the Furgeson Zones, there will be links in the description to this and more research. Once you know where your animal falls on the scale then consider your enclosure set up or desired set up and make an assessment from there. If your animal is zone 3 or 4 consider either a T5 HO bulb at 10.0 or 12% depending on the brand or a Mercury Vapor Bulb. If they fall lower on the Furgeson Index look for a 5.0 or a 6% T5 or even a quality compact fluorescent. There isn’t a wrong answer as long as what you buy puts out a UV index that is within their zone and all other aspects of husbandry are met.
So What brand to I get? Quality bulbs will produce UV as stated on the packaging. As far as I am concerned after multiple bulbs and multiple tests I have confidence in only two brands. ZooMed and Aradia. I have tested zilla, exoterra, zoomed, and acradia. In the past I have used Exoterra. I will say that I made a horrible mistake trusting Exo Terra. In fact if you are using any ExoTerra compact florecent aka coil bulbs and haven’t tested them individually with the solarmeter go turn them off right now. Seriously pause this video and do that immediately. Not too long ago I got a new solarmeter and was playing around with experimenting. I hadn’t tested all my bulbs only a couple and they were fine. I was more interested in testing my T5 HO stuff for the animals that requried those higher ferguson zone levels. But then I tested one that wasn’t on an animal because I was trying to see how much UVI it put off after a year of use. At 10 months I got bored a tested it.. It read a 15 UV Index! What the ????
I was blown away. I had been under the impression the the mercury in the bulbs was supposed to degrate over time and that as it did the bulb would put out less and less UV hence why they need replaced at 6 months and some can go 12 months. But I NEVER imagined they’d be going up in UV output. So I went to the experts and they are confirmed that poor quality bulbs can actually increase to dangerous levels rather than decrease to nothing. After learning that I tested all my bulbs. They ALL increased despite being less than 6 months old. Thankfully all but one were still in “safe” levels. One however was too high. Thankfully I believe I caught it before any irreversible damage was done. I no longer recommend ExoTerra bulbs for any use on living creatures unless you are testing them monthly maybe even weekly with the Solarmeter. If you are not you could literally be harming your animal without your ever knowing it. Here is what they say is what this bulb produces on the packaging. Here is the reading. 4 times higher than what is stated. Here is another. And another. And another. And yes this is a consistent result from many new bulbs after running for over 100 hours!!! Like I said if you haven’t personally tested it with a solarmeter turn them off NOW!!!
What do I use? I use Acradia and ZooMed T5 High output linear bulbs on my Gigdee Skinks and Berber Skinks and my tortoise. The Arcadia for the Berber is a 6% and the ZooMed is a 10.0 and the Arcadia for the tortoise is a 12%. They are reading perfect for these animals and have remained consistently. For my son’s tortoise I use a zoomed Mercury vapor bulb which is also reading perfect. For my blue tongues I use ZooMed reptisun mini 13w 5.0 compact bulbs which provides a square foot region in the cage of about 1.5-2.5 UVI through the mesh. I also measure this on a weekly basis now. I’m no longer taking chances with this crazyiness.
To recap everything. There are three main types of bulbs. Consult the Ferguson Zones and purchase accordingly. I only recommend two brands ZooMed and Arcadia. And if you are using UV and don’t have a solarmeter (I’m not paid to say this) you should. It is the only way to know what you are buying isn’t radiating your animals.
One last thing…I know several folks are going to ask what about if I have this this and that what light should I buy. I’m not going to tell you becasue this video has been all about how to figure that out on your own. So you may need to consult other sources is this one isn’t enough but I’m not going to tell you...Sorry.
Thank you guys for watching. Look another one of my videos it right down there. Go watch it! Thank you to my views, subscribers and most of all my Patrons. You are awesome. Remember, opinion is not fact.