UTH covering more than 1/3 of the tank floor?

[acharpenter]

Thinking about changing up my UTH - currently I have a 8x18" on a 40 breeder. This pic shows the UTH placement on it:

I am thinking I would like to replace it with an 11x17

This means it will sit mid floor from front to back and extend almost half way across the length of the tank.

Geek has 3 hides on his hot side so this should keep them all for the most part at about 92 and then should help get the cool side up a bit. Currently without a black/nighttime heat lamp on the cool side - it drops to about 68 or so at night.

Does anyone see a problem with adding a UTH that covers just about 1/2 the Terrarium rather than 1/3?

 

[roger]

Thinking about changing up my UTH - currently I have a 8x18" on a 40 breeder. This pic shows the UTH placement on it:

I am thinking I would like to replace it with an 11x17

This means it will sit mid floor from front to back and extend almost half way across the length of the tank.

Geek has 3 hides on his hot side so this should keep them all for the most part at about 92 and then should help get the cool side up a bit. Currently without a black/nighttime heat lamp on the cool side - it drops to about 68 or so at night.

Does anyone see a problem with adding a UTH that covers just about 1/2 the Terrarium rather than 1/3?

Am I seeing right?.You have the heating pad stuck on the side of your tank?? The UTH needs to go on the outside but underneath your tank.

 

[acharpenter]

Am I seeing right?.You have the heating pad stuck on the side of your tank?? The UTH needs to go on the outside but underneath your tank.

I knew that pic would throw someone for a loop sooner or later :main_laugh:

The tank is sitting on its back in the pic - this pic was taken when I was installing the UTH on the bottom :main_thumbsup:

So - any issues with a larger UTH?

 

[M_surinamensis]

So - any issues with a larger UTH?

Potentially issues with a larger one. You have room to manipulate them though, so probably workable.

I'm pretty sure most of this will be redundant for you, but I'm feeling a bit obsessive about thoroughness today.

Heat is energy. It helps a lot when adjusting heating elements to remember that heat is energy and to have at least a general idea about how it works. We're aiming for specific temperatures in our enclosures but we're manipulating heat in order to attain them. Heat functions in such a way that it moves to disperse through an environment to a point of equilibrium. It seeks a balance, moving from things which have a lot of energy to things which have less until a balance is achieved. Not everything conducts heat in the same way however, some materials are resistant to the energy and others are more conductive. When we're assembling an enclosure and choosing heating elements, we're introducing a heat source which will add energy to the area constantly, to prevent equilibrium and resulting in a thermal gradient (warm end, cool end) with different temperatures.

A heating pad is basically a lot of highly conductive material (metal heating elements) surrounded by an insulating material (the foam/plastic/spun ceramics) stuck under the bottom of a tank to diffuse heat up and out from where it's placed. The resulting temperatures and the thermal gradient are effected by the size, shape and placement of the heating element, by the power passing through it (ideally regulated with a thermostat), by the conductivity of the materials it passes through (the glass bottom of a tank, or the plastic bottom of a bin, any substrates used) and by the ambient conditions in and around the enclosure (the temperature of the air in the room, the movement of the air in the room, the conductivity of whatever the enclosure is sitting on and the wall behind it).

Warm rooms with better insulation will require less energy to attain the target temperature. Hot rooms risk losing the thermal gradient completely. Cold rooms often require more power and larger heating elements to get the same effect. Conductive substrates can make heating elements more efficient, insulating substrates can work against it. Insulating surfaces underneath (many heat pads have some of this built-in) or around the heating element can direct heat to the places you want it to go, conductive materials can spread it around more.

A thermostat can help regulate the temperature as a safety precaution against overheating and a thermometer can help you measure conditions where heating might be insufficient. When you're looking at changing the size of the pad though, you're mostly going to be messing with the size of the thermal gradient- heat does get directed mostly up when using the pads, but it will cause temperature changes around it as well, to the side. When using a heating element that takes up about one-third of the bottom of an enclosure, you tend to get a hot zone directly above it, a warm zone beside it and a cool zone furthest away, each about 1/3rd of the floor space. If the pad takes up half of the bottom, then you get a 50% hot zone, a similarly sized warm zone and a greatly reduced cool area. Ambient conditions and the conductivity of whatever is lining the bottom of the enclosure can dramatically alter that, but it basically pushes the hot side further towards the middle of the enclosure.

You can technically do the math to figure it all out on paper but frankly it's usually a lot easier to just try things out until they work. Big pad, small pad, thermostat turned high, thermostat turned low, insulation under your cool end if it's too hot, conductive materials to direct heat where it needs to be if it's too cold. Adjust as needed to compensate for seasonal changes in the house depending on your use of heating and air conditioning.

So the risk of using a bigger heating pad is the possible reduction of a cool area. You can use insulating or conductive materials to help direct heat to the areas you want it to go, to either increase the effectiveness of a weaker heating element or to prevent a more powerful heating element from disrupting the gradient. You can also potentially use multiple heating elements in conjunction with one another to create the desired zones of temperature if one ends up being too difficult to manipulate by itself.

A little forethought combines with some trial and error generally does the trick, you can run through the exact physics of it all if you really want and happen to have the appropriate tools laying around to measure it all with. I usually find it's best to set up an enclosure and monitor it for at least a couple days so that I can make adjustments if needed before introducing the animals to it, especially if it's a new set-up with a new heat source and new substrates.

 

[fl_orchidslave]

Personally, I would buy a foot of 12" heat tape and the connector clip, using a slate floor tile underneath to press the heat to the glass. For a tank that size this would give a nice area of about 92* and still allow a good temp gradient. Leos need the cool as much as the heat to properly regulate their metabolism.

 

[acharpenter]

Hmmmmm - that totally makes sense Seamus - thanks for the info.

We are moving in a month or so and I plan to build a faux structure (substrate, walls, hides, ledges etc) out of styrofoam after we move. Perhaps for now I will just mess around with some slate tiles to help distribute the heat and see how that goes.....

After we move I will have an extra breeder tank I can test out the heating in along with the faux structure....will also be able to test in the new room they will be housed in (loft area), as I am sure the temp variables will be way different. Currently they are hosued in a lower level office

Thanks for the suggestion Laney - will keep it in mind for when I am testing the new set up

Thanks for you help!