Does substrate raise or lower temperatures?
I have 2 tubs, 1 with newspaper and 1 with sanichips in the same rack. When i use a tempgun on the newspaper, I get a significantly lower reading than i do with the sanichips. I figure this is for 1 of 2 reasons
1. the newspaper is slightly raised or curled above the surface of the tub, creating a cooler air pocket.
or
2. The tub filled with sanichips is holding heat better than than newspaper, even though the 1 inch of chips keeps the snake further from the heat source.
Does substrate make that much of a difference?
Also, when using a thermometer with a probe, should that probe be on top of newspaper or under it when measuring the basking spot?
Re: Does substrate raise or lower temperatures?
A thin sheet of newspaper is not going to hold heat and radiate it the same way half an inch of sani chips will. While yes, the animal is technically further away from the heat source when the sani chips are inbetween it and the heat source, there is also a layer of sani chips that is heating up.
The sani chips take up space within the tub, so there is less open area to be heated, compared to the tub with newspaper. In a hatchling sized tub, this difference can be enough to create a noticeable difference in temperature. In larger tubs, I generally don't find this to be the case as much, although it can still happen, especially with a thick layer of substrate. The combination of less air to be heated, and more surface area (the substrate, and the tiny air pockets within the layer of substrate over the heat source) being warmed up in addition to the actual heat source, may be enough to create the discrepancy in temperature that you are describing.
-Jen