Need Help with Bulb Height and Heat Coverage

[Oxalis]

Here are the details on our 16 sq ft indoor Russian enclosure: http://tortoiseforum.org/thread-80648.html This thread has all the developments on the tortoise table and materials, with photos up to today. We'll have an Exo Terra UVB mercury vapor bulb, 125 W, with an 8.5'' dome lamp. At this point in our enclosure project, we could really use some insight on about how far the bulb should be from the surface of the substrate and about how large the heat coverage from this bulb would be. I do think someone else on the forums said that the bulb had to be less than 30'' above the substrate surface. We have not set up our lamp for this table yet, and we have the possibility of using a second, smaller heat lamp as well, if need be, since the surface area is 16 sq ft. I assume that even with the 125 W bulb, my tortoise will still have a cooler area of the table to go to if he feels too warm. We also plan to make the lamp heights adjustable for the change of seasons or other factors. The one parameter we have to work with, however, is spacing the heat bulbs far enough away from the plastic liner so it doesn't melt, or heat up the wooden walls underneath. Any input is greatly appreciated!

 

[mikeh]

At 30" you will not get enough beneficial UVB or heat. Russians are arid species and need good amount of UVB and basking heat. With your open table and 125w bulb distance of 15" from the top of his shell to the lowest part of the bulb is ideal. Place the bulb facing straight down, in the middle of enclosure. Don't worry about hot spot being above 100F, he has plenty of room to maneuver around to thermo regulate. If the room is on the cool side he may actually prefer it hotter. You may also need additional daytime heat source.

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[WillTort2]

Your going to have to experiment with your bulb and your enclosure to determine what height you need.

I've never used the 125 watt bulb, but with my 100 watt bulbs, they range from 14" to 19" depending on your air flow and substrate and dampness. I try for a 95 to 100 degree basking spot.

I would suggest using both a probe type digital thermometer and a temperature gun. For a new bulb, read the instructions for burn in time before putting the tort under the bulb.

I would place the bulb pointing straight down near one of the corners. This should allow the far corner to be your cool side. You may also want to put a few divider walls in the enclosure to add interest for your tort.

Let the temperature be your guide for height, try starting at 24" height.

 

[Oxalis]

At 30" you will not get enough beneficial UVB or heat. Russians are arid species and need good amount of UVB and basking heat. With your open table and 125w bulb distance of 15" from the top of his shell to the lowest part of the bulb is ideal. Place the bulb facing straight down, in the middle of enclosure. Don't worry about hot spot being above 100F, he has plenty of room to maneuver around to thermo regulate. If the room is on the cool side he may actually prefer it hotter. You may also need additional daytime heat source.

Thanks! That's a good point that he'll be able to maneuver around the heat. The room is on the second floor so it is generally on the warmer side, and it's on the south side of the house, which gets all the sunlight.