Still confused about proper UVB lighting


New Member
I'm wondering if any experts out there can give me some definitive answers. I know my screed is rather long, but I'd very much appreciate if you could take my questions on one my one. I've given them a lot of thought, but am not having much success in getting solid answers. I'm sure these answers would benefit a lot of folks besides me. And if these questions have already been answered elsewhere, my apologies.

I've not yet gotten my male juvenile veiled although I have gotten the enclosure and many accessories. My question is about correct lighting. No problems with the basking light: a hooded incandescent above the basking spot that produces a temp of between 95 to 100 degrees F is easy and straightforward.

I bought an LLL reptile all-screen enclosure, 18x18x36" for my future 4-5 month old veiled male, a basking light above the basking spot that produces the requisite temp on a branch perch about 6 inches below the light and am working to get all the conditions right before I take delivery of the cham.

I know that the conventional wisdom says that for an enclosure of this size a ReptiSun 5.0 with a hood that is 20" (18" tube) is right.

But I'm getting information from people who seem to know what they're talking about who says that the Reptisun 5.0's UV rays only reach down about 6 inches and for that reason one should really get a Reptisun 10.0 for an enclosure of that size (36" to 48" high).

My specific questions are these:

1. For a cage that has a 18x18 footprint and is 36" high, is just ONE Reptisun 5.0 sufficient as long as the tube is changed out every 6 months?

2. Would either two 5.0s (two-tube hood) or one 10.0 be better or is that too much UVB?

3. Is there such a thing as "two much UVB", in other words, would two tubes on for about 12 hours a day be too much? I often see on this forum that people use a one-tube or two-tube fixture as if it really doesn't make much difference. One breeder told me that she uses a 5.0 only for babies but a 10.0 for older chams. Another one suggests using two 5.0 tubes. And on this website:

the write says he uses THREE 24" tubes over 2.5'x2.5'x3' veiled cage. Why such a diversity of opinion on what's right?

4. Because I don't like the look of the tube hood sticking out past the edge of the cage on both sides (I know, health should come first), I purchased an 18" hood to exactly match the width of the LLL cage. Since the hood holds a 15" ReptiSun 5.0 tube, will I not be providing enough UVB for the cham on the edges? Dodalah has already advised me NOT to purchase the 18" hood and instead get the 24". Not to question your expertise Dodalah, but just wondering what others think about that. One breeder I spoke with said it really wouldn't make much difference.

5. When the cham is larger and I upgrade to a 24x24x48" enclosure, would a 24" hood (flush to edges of enclosures) with an 18" tube be sufficient, or should I just bite the bullet and get a 30" hood with an 24" tube even though the hood sticks out 3" on each side?

6. The LLLReptile hood I purchased holds only one 15" tube and has no reflector. Is a reflector "optional" or essential? Again, either the cham is getting enough UVB or he's not; I can't imagine that it really doesn't make much difference. I've heard that a reflector, even a piece of aluminum foil placed inside the hood, does make a big difference in the amount of UVB getting down into the cage. Why aren't all reptile UVB hoods supplied with reflectors if it does make a difference?

Again, sorry for the longwindedness, but these are important questions. I don't want my critter to suffer from MBD, so I want to get it right BEFORE I take the plunge.

Thanks so much for your advice.:)


New Member
2. Would either two 5.0s (two-tube hood) or one 10.0 be better or is that too much UVB?

3. Is there such a thing as "two much UVB", in other words, would two tubes on for about 12 hours a day be too much?
Ultraviolet radiation is expressed in microwatt per square centimeter (mW/cm2) and varies tremendously from the poles (low) towards the equator (high). The amount of UVB radiation received on the equator on a clear day at noon is around 270 mW/cm2. However, this high amount of radiation decreases as the day passes, in the same way that it had increased since sunrise and taking into consideration that not all days are clear. In the wild, basking activities of most reptiles are limited to the early morning and later afternoon. The rest of the day is spent in the shade, in burrows, crevices or other shaded places, or at various places in leafy bushes, shrubs, or trees. In tropical forests, home to many types of reptiles, only a little direct sun penetrates the forest canopy and underlying layers to reach the ground.

Many commercial reptile lights exceed this 270 mW/cm2 in attempt to show the greatest UVB radiation. Some even exceed over 2000mW/cm2, which is absolutely dangerous! Especially if you know that the 270 value of the sun is only measured at high noon on a clear day while most light bulbs are on between 10-12 hours with constant values. Reptiles accumulate these UVB rays during the day (10-12 hours), so there is absolutely no need to even emit 270 mW/cm2 continuously.

CONCLUSION: More is NOT always better!

(quoted from EXO-TERRA's lighting guide)


Retired Moderator
Gideon for 18 18 36, I believe 1 uvb 5.0 reptisun and 1 heat lamp is enough lighting for him.
If you want better coverage buy the 18" tube with slightly bigger fixture.

Even for 24 24 48.. I don't feel the need to get 2 reptisun 5.0 or use a 10.0
Just provide a clearing area (no obstruction from branches or leaves) where he can bask to his heart content.
Be sure that when he bask on his spot, he get BOTH heat light and uvb light on him. Don't separate the heat lamp and UVB too far. I do no think chameleon is smart enough to bask back and forth on 2 spot between uva and uvb.

Since you live in California especially, you will have lots of time putting him outside through out the year.

With that combination + proper supplement as backup plan, you will have a chameleon with a strong bone density.

Reflector is a nice addition to boost the strength of your uvb light.. but not absolutely necessary. sort of like an auto mister... definitely handy to have, but your chameleon won't die from the absence of an auto mister (provided that you manually mist the cage).

The secret lies in how you provide the chameleon with means to get close to the uvb source without harming itself and to get away from the uvb if it need to.. It makes more sense to me to let your chameleon judge how much uvb it needed on its own.

Therefore, don't overkill your husbandry with overcompensation.
If you really want to be specific about it, then i suggest buying a UVB meter.
and measure the strength of the uvb.
To my knowledge, in his book, Dr. Ferguson recommend people to provide 5-15uW/cm2 of UV-B for 12 hr/day.

We talked for a while via email. I think you have done a tremendous research (and I can see how serious you are in this hobby).
Now, purchase the supplies, build the cage, and have fun with decorating the enclosure.
Take a pic, post it in here (or email me if you prefer) for crits, and get ready for a happy chameleon coming your way.

Depending on your locale climate and your chameleon needs, your husbandry method will vary slightly here and there compared to other people.
As long as you maintain the basic rule and some common sense, you will be able to adapt your method to meet your chameleon's need.

Don't forget.. having chameleon can be fun too. Soon, you'll be buying another addition and again and again and again... Depending how severe your addiction is :D
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New Member
Hello i am also new and have done a ton of research before getting my cham! I am getting a sambava panther, my cage is all screen 24Lx12Wx24H and have reptisun 5.0 that i beleive needs changing every six months??? and a basking light with zoo med 75 watt basking bulb. Everything is set up and ready for him i have a ficus benjamin inside with branches and vines on the other side for climbing. with all this in mind my question is when and what times should the lights be on? Do i turn everything off at night? or one of them? this i am unsure of? i beleive as i have read in tons of other forums here the reptisun should be on 10-12 hrs in day only but what about basking light and at night? any info would be great! I also built a plexiglass drain for underneath the cage similar to the one someone has made on this forum. i think it turnes out great! If anyone is interested let me know! easy to build!


New Member
a reflector pretty much doubles your output. i have added aluminum to mine to increase the amount put out. at a normal 6-12 in reading different companies i think have different standards for measuring, but thats where the 5% uvb is at. more closer to the bulb less further away. by using a reflector you going to get the entire force of the bulb rather than just one side. this also keep you in the same UV range such as you R G B on track rather than doing a 10.0 thats has higher R spectrum. shows this right on the box.


Chameleon Enthusiast
A reflector is a good idea in this instance, since you are using a fairly dense screen material (which will block some uvb) and a slightly smaller tube.


New Member
A link or anything would be great! i have literally been searching for hours on how long and what times to run the lights? my main question is do i run them t night? if temp falls below 60 what should i do? get a different basking bulb just for night? and swap it out? and if i only run reptisun 5.0 for 10-12 hrs a day how long do i run the basking light? i am super confused on this! Please help!


New Member
you will run ur UVB/Basking all day. best thing to do is a 12-12 hr lighting cycle. once they get on a cycle they tend to stick to it

if it gets below 60F then you will want to do a Ceramic heat bulb. its controversial on the forums to use a black light to keep heat up.

reptisun, or another uvb bulb will not put off heat (florescent tubes only)


Chameleon Enthusiast
Ceramic heat bulb (emits no light) is an option for at night heating. Better to just heat the room so that it doesnt go below 65F. :)

I have the UVB lights come on a little after the heat lights. In Winter the lights are on for fewer hours than in Summer. But a 12 on 12 off cycle year round is what many do.


New Member
Thank you everyone! I have read so many forums I beleive I got confused on what to do! Most everything tells u something different! I live in Alabama so humidity is horrible here! It is 62% in my home and that is normal, I have checked it a lot over the past few days and seems to always be around 60! I guess when my Cham gets here I wouldn't have a problem keeping humidity up. :) I checked my cage with all lights out and it is about 70-71 at night so I guess that will be ok to shut everything off?


New Member
Lots of great advice given here, I personally think the best of it is to get the animal outside as often as possible for natural Uv, whatever artificial sources you use!
Nobody can or ever will ,replicate natural uv in any artificial form.
Enjoy your chameleon. :)


New Member
Take a look here....


and then take a look here...


Hope it helps.
Great links thanks!!! :) So with that info i read they need around 18-33 in a 12 hr period. but if i use foil with screen i get 34 and without foil through screen u get 18. so wich is better? the 34 seems maybe to much! where the 18 with just the screen may not be enough? is 34 too much?


New Member
One more thing......I have a 75w zoo med basking bulb and checked the temp last night with the basking fixture sitting right ontop of the screen like i see most everyon does and the heat was crazy hot like 120 5-6 inches away! should i get a smaller wattage say like a 40w? or try and raise it up off the screen? and will a normal houshold bulb be just fine orhave to get the expensive ones like zoo med or others? Also like to say Thanks for all you guys help i am sure this is all posted in here somewhere but there is just so many threads i have spent hours and hours reading and keep coming up empty handed! My cham will be here tomorrow and i want to make sure he is taken well care of! and everything is perfect for him!! im kinda in a panic! this is my first one! i have studied and reasearched for a month now and just want to make sure everything is correct!!!:D


Chameleon Enthusiast
One more thing......I have a 75w zoo med basking bulb and checked the temp last night with the basking fixture sitting right ontop of the screen like i see most everyon does and the heat was crazy hot like 120 5-6 inches away! should i get a smaller wattage say like a 40w? or try and raise it up off the screen? and will a normal houshold bulb be just fine
Yes, a lower watt regular household tungsten incandescent bulb. Or raise the bulb you already have a distance off the top of the cage, until the basking spot is a more reasonable 90F

everything you ever wanted to read about lighting and heating:
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