Reptile & Amphibian Forums

I just got a 40 gallon tank for my mali and was wondering if I should go with a mercury vapor or Reptisun UVB 10.0 with a separate heat bulb?

Thanks

The Mercury vapor is unquestionably better. You get the heat, the best uvb next only to the sun, and really good light all in one place.

The MVB will cost about a third more initially, but it will last two thirds longer if you get a good one like a Megaray or a T Rex. The best tube needs to be replaced after 6-8 months, and the MVBs have been tested and produce more than adequate levels of UVB for 18 months or longer. Its best to replace them at a year to 18 months.

I promise I'm not a MVB saaaalesman, just an addict!

Will you have a screen on the top of the tank? If so, the MegaRay might not work because you don't want it sitting on a screen.

Several of mine sit on screen tops. I know that some of the UVB is blocked but they obviously get enough. Is there another reason that they shouldn't be on the screen?

I also raise some of mine a few inches up to accomodate distance from the basking spot. If you get a 100W, it needs to be no closer than 12 inches from the basking spot.

When they sit on the screen they retain a little more heat, which can cause increased decay or blowout. This is more common with powersun and other bulbs of less sturdy construction, but could still make some difference with megarays or trex. I own a meter and it seems to me the lower the wattage(less heat), the slower the decay. I have noticed the 60watt barely decays at all for a very long time,and the 100's last much longer than the 160's.(uvb wise) So it makes sense that it is the heat that largely contributes to decay.

So you are saying that they become less effective if on a screen? I have several that are 18 months plus and still burning. It would be a good idea to get a meter, I guess. I usually start replacing mine at 18 months, and my animals are all super healthy. ???

It has always been my understanding not to let the bulb touch the screen, and I know this to cause Powersuns and similarly constructed bulbs to blow out. The screen gets hot and is in contact with the bulb so the bulb is hotter than it would be normally.Megaray has much better construction and thicker glass but it is likely to cause a similar situation, although I am sure the megarays and T-rex handle it better. But I really do notice that the more heat the bulb produces the faster it decays, in general. I also have bulbs that are still going strong visibly and heatwise but are producing very low amounts of uvb.(I keep them in case one blows out to use while I wait for a replacement) They decay long before they blow out for the most part. I only had one megaray fail before it really decayed and that was an EB that I used for about 18 months, in the last month it started to decay a little but was still very strong, then started blinking and flickering. I don't have screen tops so I can't tell you for sure but as a general rule bulbs should not touch the screen. AS for replacing every 18 months, your bulbs probably still produce uvb but not nearly as much as when new, but it is likely they produce more than a tube that is only a few months old. And some are probably doing better than others. If you don't get a meter, I would say to replace them in spring every year for 100 watt megarays, rather than 18 months.

I know you have other reptiles, but I am not sure what kinds, but for the uros and beardies you can give them new ones in spring, then give iguanas or whatever the uros and beardies old bulbs, as some reptiles need much less uvb than the desert diurnal types. You may notice when bulbs are new, some of your reptiles may bask toward the outside of the "circle" and as the bulb ages they move towards the center, while uros will bask right under it and later in the day stay to the outside, and then go directly under another heat source. Photo-regulation, it is called. I think you may find a meter would be very handy for this type of bulb rotation-just a suggestion.

You know, I do rotate my bulbs, especially when I get in a sick rescue. I can rotate the older bulbs over to the spinys I guess. But the other thing is that I get giant domes. My bulbs don't touch the screen at all. They are a good inch or two up off of it. But, I could custom make some lids or cut a bulb hole?

For the beardies, half of the tanks don't have lids. The other half only have lids because I don't have boom stands for the lights. The collareds and spinys MUST have lids as they are little acrobats. The uros probably don't need lids except the ones that are housed in the bird room. I do let some of my birds out to fly every day.

What about the Desert Iguanas? Are they high UVB dependent?

Not sure about desert iguanas,it depends on basking habits and daily routine, pretty much what they go by in figuring uvb dependence out, other than a few tests here and there on one group of animals or another. If the bulb doesn't touch the screen it will probably not create any problem other than blocking some rays and also some heat, you just don't want the glass getting hotter than what is "normal". Bob's site says somewhere how much heat and light is actually blocked by screen, and some basic guidelines for UV requirements. He could probably tell you how much closer you can have the bulbs when used through screen, as the recommended distance is based on uv output, as long as the temps are still good.

...so check with him, and maybe you can compensate by just raising the basking spot. Although I am sure he will say brighter is better,better with no screen for the uros.

Well, I bug Bob on a regular basis, so next time I talk to him, I'll ask. He is a super resource of info on rehab.

My temps are good as per a temp gun. But, it wouldn't hurt to try to eliminate the screens.

The local pet store has Exoterra Solar Glos at 125 or 160 watt. Are these any good. Also, what wattage would be right for a 40 gallon breeder?

Thanks

The Solar Glos aren't bad. I have a 160 on my 40 breeder uro tank, but that would be way too hot for other kinds of lizards. You can get the 125 and add extra bright regular household bulbs if you need to bring the heat up. Even with the 160, I had to add bulbs this winter, but I am removing them now that the weather is HOT! LOL! I'm in SE Texas, and it is already getting into themid 90s here.

BTW, I don't use the Solar Glo. I only use Megarays. The Solar Glo is pretty good. I'm not sure if it is as good as the T Rex or Megaray. It IS better than the power sun!

Selection of bulb is going to depend entirely on your set-up. I use zoo-med's 5.0 linear fluroscent in my uro set-up, but he can get right up to the bulb if he wants... anything else would be too much. My setup is a 20L for a juvie saharan, so a mercury vapor bulb would be too dangerous. Zoomeds generally have slow decay and in my experience last longer than other bulbs. Having said that I do think that they (reptiles)react more favorably to the Mercury Vapor bulbs, and I have seen instant changes in behavior, most likely due to the increased UVA. There have been some issues with the Zoomed COMPACT fluroscents as well as a few other brands of COMPACT fluroscents. I do not know if these issues have been corrected yet, so it may be wise to stay away from those bulbs.

I have seen marked changes in color and behavior as soon as I put a MVB over a lizard, and seen this many times in rescues. Seeing is believing.

Here is the uvguide study. It discusses the problems with the coils and compacts, and discusses the effectiveness of other UVB sources, including MVBs and the better linear tube bulbs:
www.uvguide.co.uk/