Does the bulb make a difference?


Avid Member
I would like to share a personal observation about UVB bulbs. I have done no scientific studies, so I will not attempt to draw a scientific conclusion.
This is a long post. Read it if you will...

I've had my male Veiled chameleon since he was about 5 weeks old. He has lived in three different cages in the time I've had him.
The first cage was a small one I built specifically to accomodate him as a really young chameleon. He lived in that cage for about 2 1/2 months.
I used a 30W (90cm) Exo-Terra Reptiglo 5.0 bulb on that cage for UVB. It was too large for the enclosure and the bulb stuck out over the ends of the top of the cage.

I then moved him into another 'juvenile'-sized cage, because my new design sorted out a lot of the drainage issues I was having with the first cage.
For that cage, I bought a 20W (60cm) Exo-Terra Reptiglo 5.0 bulb that was better suited to the size of the cage.

Then when he was about 7 months old I moved him into an adult sized cage where he still lives today (just over a year old now).
For the adult cage, I initially used the same 90cm Reptiglo 5.0 from his first cage.

Everyone (including the pet-stores that make money out of this) recommends that you replace the UVB bulbs every 6-12 months. And I'd seen the UV Guide tests that showed that the Reptiglo output was quite a bit lower than the Zoomed bulbs.
So I was happy to stick to the conservative estimate and replace my bulbs after 6 months of use.
The initial 90cm bulb had only been used for 2 1/2 months in the first cage, so I estimated that I could use it for another 4 months or so in the adult cage.

At around 8 months, my chameleon started eating a lot less. Being a Veiled, he had always been a voracious eater and quite an active hunter.
Initially, I dismissed the change as being part of him getting older: adults eat less than babies.
But then he started going on what seemed to be 'hunger strikes'. He simply refused to hunt down any crickets in his cage. And he wouldn't eat any even in a bowl.
I was told that Veileds can be fussy eaters. So I tried to diversify his meals as much as possible. There were initial successes: upon being offered a new feeder (e.g. superworms, mealworms, silkworms, soldier flies) he would initially eat a lot of them, but then not touch them again for days.
So there were many days that he wasn't eating anything.
I reviewed my husbandry in precise detail (temps were fine, humidity was perfect, drinking and hydration was good, gutloading was religious, dusting was textbook - he was even getting regular doses of sunshine outside). When nothing seemed to be at fault, I started worrying that something more serious was wrong.

Before that he had been growing consistently, now his weight was staying constant - it even looked to me as if he was getting thinner: seemed like less meat on the bones.

So I took him off to the vet. But everything checked out. Bone structure was solid, fecal tests were clean (so that ruled out my suspicion of parasites), calcium levels ok.
The vet assured me that they went through phases, and his loss of appetite could possibly even be linked to the onset of winter and colder ambient temps.

But a few weeks back, my 6 month mark had been reached on the UV bulb in the cage, and there was a reptile expo in town, so I took advantage of the show prices and got some Zoomed Reptisun 5.0 bulbs to replace the Reptiglo ones.
It's been almost 4 weeks since I've had the new bulb in the cage, but the change in behaviour was almost immediate. In the first week with the new bulb, he started eating way more food.
From eating about 1-2 crickets/superworms a day, and sometimes even skipping meals for a day or two, he has now been averaging about 6-8 medium/large crickets a day for the past 3 weeks.

And apart from the light, nothing else has changed. Lights are on the same timer schedule, mister is on the same schedule. Insects are the same sizes as before, and on the same gutload/dusting schedule. Plants are the same.
I've been monitoring the temps, and the ambient and basking temps are the same (if anything, it might be a tad cooler, since it snowed briefly here last night for the first time in about 15 years).

As I said, I have no scientific data to help me come to any conclusions. Was it the brand of the bulb that made the difference (UVGuide would seem to suggest that)? Or was it the age of the previous bulb? (I can verify that the previous bulb had come from sealed packaging, so it was brand new when I started using it) Without a UV meter I can't tell what the difference in output is.

All I know is that since changing the bulb, my cham has been more active and eating more than he has in the past 3-4 months. He seems healthier than ever.
interesting...! If it really is just from changing brands of bulbs that says alot about reptisun's superior product quality compared to the exo terras.

I'll definately be buying zoomed's bulbs once my 'stock' esu one is du to be changed after reading this
Just curious. I have the reptisun 5.0 no my young veiled's setup, but where do you guys place them at above the cage? I have mine in the front of the cage with the basking light in the far back right corner. The reason I ask is that the chameleon stays in the back for the most part and never seems to be under the 5.0. Does this bulb radiate throughout the cage so that he is getting the UVB even in the back?

Also - No problem with eating. He is putting down 10-15 crickets/day.
I have found differences in the chameleon depending on the bulbs used over the cage. When I got to the Repti-sun 5.0's I liked them and have stuck with them as much as possible. (Sometimes I have to substitute if my supply runs out and the order is late coming in.
if the cage has a fine screen top that the light has to pass through it can limit the amount of UVB entering the cage by up to 50%

From all of the various studies that I've read, I'm also sticking with the ZooMed Reptisun 5.0 straight tube. I still have issues with the coil type. I invested in a Solarmeter 6.2 UVB meter ($160) a few years ago and find it very useful to check tubes as they age. I'm a member of the UVB Meter Owners forum and unless you have $1000's, the 6.2 is the one to get.

If your critter can get within 6" to 12" from the tube's surface for ~12 hours a day (with or without screen in the way) then it will probably get enough UVB.
I have seen and heard that alot of veileds that go through a phase of eating less in the same time frame you are talking about. Mine did.
This is a really helpful thread! I appreciate the information you've brought out about the variation in UVB output of different products, because I would never have known it was even possible otherwise!

Thank you!

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