Reptile & Amphibian Forums

Hi,
I have a question regarding heating a 30 gallon glass tank. I already have an UTH that works with Infra Red heat stuck about one third the length of the glass tank (below it). According to the manufacturer it raises the temperature of objects but not the ambient air temperature. When testing the heater, I placed a thermometer on the glass bottom right above the heater and one about 6-7 inches right above the tank bottom (above the heater part). The gauge at the very bottom showed about 90 degrees whereas the one about 6-7 inches above showed about 74 degrees (which is room temperature) !!!
So my question is: is this enough for a terrestrial snake? OR should I also try to raise the ambient air temperature as well? Is it OK to have a warm spot which is only warm on the very bottom but not the air above it?

Thanks you in advance.

Are you measuring the temperature with any kind of substrate? If not, keep in mind that some substrates, or any THICK substrate, will reduce the effectiveness of an UTH even more. It's best to stay with a fairly thin substrate layer if you are using a UTH with nothing else.

But it is a common problem in glass tanks with screen tops to only have a hot area at the very bottom of the tank, since all of the other heat will escape out of the top. You might affect this by putting some sort of cover over the screen top (such as foam insulation board or plastic, leaving a small area for ventilation).

However, if your snake spends most of its time ON the cage floor, and the temperatures measured at the floor level above the substrate are warm enough, this may be acceptible. If your snake is more of a climber at this point (I know you said "terrestrial" but sometimes younger boas like to climb), you may want to add an overhead heat source as well.

The problem you're having happens a lot with glass tanks especially in colder climates - I know I went through a LOT of heaters when I primarily used glass tanks, and now have moved to other types of enclosures instead.

Good luck, try insulating the top (and some people insulate the back of the tank, too, with Reflectix or foam insulation to help keep some more heat in) and see if that helps.
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Lauren Madar - OphidiaGems.com
1.0 Ball Python, 1.0 Hog Island Boa (RIP DeeDee), 1.1 Hypo BCI, 1.1 Surinam BCC, 0.1 Green Tree Python

If not, keep in mind that some substrates, or any THICK substrate, will reduce the effectiveness of an UTH even more. It's best to stay with a fairly thin substrate layer if you are using a UTH with nothing else.

That's a bit misleading. A substrate, even a thick one, can increase the effectiveness of a under-tank heat source by increasing thermal mass. In fact if anything it's best to have thermal mass in a glass tank when using only under tank heat.

I went into this in more detail on the caging forum where this topic was cross posted.
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Current snakes:

0.0.1 Gonyosoma oxycephala - Java locale (green)

1.2 Gonyosoma oxycephala - Jave local (green)

2.2 Gonyosoma janseni - Seleyar locale (all black)

1.2 Gonyosoma janseni - Celebes locale (Black & Tan)

Sorry if I worded that in a misleading way. I meant to say that too thick of a layer of substrate over a UTH can have an insulating effect, trapping all of the heat below or in the substrate, and not allowing it to get above the substrate and into the tank. For a burrowing snake, this would probably be ok, but for a snake that just hangs out on top of the substrate, temps need to be measured at the surface of the substrate.

Sorry if I was unclear.
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Lauren Madar - OphidiaGems.com
1.0 Ball Python, 1.0 Hog Island Boa (RIP DeeDee), 1.1 Hypo BCI, 1.1 Surinam BCC, 0.1 Green Tree Python

That's better, but again with certain substrates thicker can be better as it increases thermal mass and can help distribute the heat.

Just look at radiant floor heat used in bathrooms, etc. If you took all that heat cable and just draped it out in the open around a bathroom it would have little heating effect, even if you had it heated super hot.

But then bury that heat cable in a thick bed of motar and cover it with heavy tile and suddently that same heat source can heat the room. Why? Because the heat from the cable can move conductively into the motar and tile which then heats up and radiates into the room.

I guess my point in all of this is that the a sterile setup in a glass tank in a cool room can be a very bad setup for the animal in question. That situation needs some thermal mass just like the bathroom example described above.
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Current snakes:

0.0.1 Gonyosoma oxycephala - Java locale (green)

1.2 Gonyosoma oxycephala - Jave local (green)

2.2 Gonyosoma janseni - Seleyar locale (all black)

1.2 Gonyosoma janseni - Celebes locale (Black & Tan)

Thank you both for the useful information. The substrate I currently use is simple newspaper, and of course that gives no thermal mass at all. My glass tank has a strange top which is made of glass with a mesh cut in the centre; this makes it impossible to add a heat lamp as the mesh cut is only 2 inches wide. I believe that my options are limited to adding another heat mat in the back of the tank, but this time choose a heat mat that does not only heat with Infra Red heat (such as the ones from ZooMed). I will also try to add some objects in my terrarium above the heat source which will act as thermal mass.

Thanks again.

np
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Current snakes:

0.0.1 Gonyosoma oxycephala - Java locale (green)

1.2 Gonyosoma oxycephala - Jave local (green)

2.2 Gonyosoma janseni - Seleyar locale (all black)

1.2 Gonyosoma janseni - Celebes locale (Black & Tan)