Different temps with different substrates?

[Alice]

Has anyone done any research or does anyone just know if different substrates conduct heat differently? Let me explain . . . over the last 1 1/2 years we have moved from newspaper, to mulch and now recently to aspen. We did not change the heat setting of our Helix or Herpstat II, neither did we change the position of the heat cable. However, when we check the temps in the tubs with the aspen, it seems to be lower than it was with the newspaper and the mulch.

Now I know that humidity is impacted significantly with different substrates - mulch holds moisture when new and thus has a higher humidity than aspen or newspapers. But I didn't realize that there could be a different tub temp with the different types of substrates.

With the probe placed on the heat source, if different substrates do conduct heat (or insulate as the case may be) differently, does it seem reasonable that we would need to adjust the thermostat to get the temps in the tub equal to what we need for a BP?

I would appreciate hearing form anyone who has experience with this situation. Thanks everyone for all you on-going help and encouragement!

[jenakle]

I'm still learning about this too. In a 30 gal breeder (glass tank), I've used newspaper (had to adjust heat WAY down), and varying levels of cypress, aspen, or a combo of both. The cypress stays too moist, and the mixture of aspen seems to be working well, but I have the temp/humidity gauge in the tank constantly. I have an UTH on one side, turn a lamp on during the day for extra warmth, and seem to be constantly adjusting the rheostat (it's a fairly new set-up, in a new room...the old 30 gal did well once the bedding was in and everything was settled for a while).
My next step is to enclose the breeder top a bit, since the screen is likely letting the A/C in/heat out more than I'd like.

[elevatethis]

Its more about the thickness of the layer of substrate in which you are using on the bottom of the cage, certainly if you are using a UTH like flexwatt.

Basically, a thick layer of substrate would serve more as insulation against the heat rather than conducting it through to the rest of the cage.

If your cage temps aren't where you want them to be, use less substrate on the floor. Another dimension to this is that the more substrate you use, the less you tend to completely change it out. Using a thin layer will boost your temps as well as make it easier to see when the cage needs to be cleaned. You'd be suprised how much urine can build up at the bottom of a layer of repti-bark or aspen shavings....