# Probe positioning for heatmat?



## stylecreep (Aug 18, 2014)

Hi guys, 
I have a glass viv with heatmat underneath (outside) 
I have had probe above the thin layer of substrate and temp is reading around 28. It's for a royal python. 
I've just put the probe under the substrate into the glass above heatmat and it's flown up to 37! 
Before I was concerned it wasn't hot enough, now worried I'm cooking him! 
Where is best to position probe? I thought on substrate, but if the burrows down a little maybe he'll get burned? 
I have a new double stat arriving today and will add a mild night heat lamp also on dimmer. Just now worried about how hot should mat should be getting! 
Thanks Sam


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## Athravan (Dec 28, 2006)

If he's a burrower I would put it underneath the substrate. That's a really big temperature difference for just being on top or underneath the substrate - none of my tanks have that sort of gradient. You may want to get some polysterene sheets and put them between the glass and the heat mat to add an extra layer if the heat mat in direct contact with the glass is causing a problem.

Do you also have ventilation around the heat mat? You do not want a solid tank directly on top of a heat mat, if there is constant pressure on it the temperatures will be much higher, and it also has a higher chance of malfunctioning. A glass tank can weigh a lot, so ideally you'd want it to be raised slightly, even if just a few mm with feet or again, with polysterene sheets or even some cardboard just so the air can get into the gap. If you take a look at the Exo Terra tank bottoms for example, the actual glass is raised approximately 1cm off the ground by the plastic edging, so there is a constant air flow underneath the tank.

You could also try the heat mat on the back of the tank which will be much better ventilated.


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## stylecreep (Aug 18, 2014)

Great, thanks. It's a exo terra viv which is has raised lip around base so it's not directly on mat, but I had put some cardboard under mat to insulate pushing it up into glass. So I've removed this now to leave a bigger gap. I just hadn't expected the mat to be that powerful. He's not burrowing, yet. I have 2 vivid set up with same problem. 1 has inch and half layer of aspen, other has under inch of bark. Think the viv with bark should now be easier to control. The aspen; maybe is too thick a layer which is why such huge difference. Really appreciate the advice! Also, another stupid question; the mats don't display which side should be up? Is there a difference between the top and bottom of Mat?


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## Hannah81 (Nov 19, 2008)

Yes, the side with the metal strip round the edge is the underside.

Where is the thermostat probe placed?


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## stylecreep (Aug 18, 2014)

Thanks Hannah, metal strip down. I hadn't purchased a thermostat with it as was told it would be ok, but realised not, I have ave one being delivered today though. Thanks !


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## clumsyoaf (Oct 23, 2012)

Hiya, unless you will be keeping your royal in a exo-terra for life he may be better off with either an IR bulb or a ceramic heater, with the stat probe half way down the back wall. This will improve the ambient temperature and is more common when royals get bigger because of the pressure on the heat mat! Otherwise, when using heat mats I bury the stat probes into the substrate so my animals don't burn themselves.


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## stylecreep (Aug 18, 2014)

Thanks clumsyoaf! To be honest the exoterra was a quick cheap option when I was at kempton, I'm sure he'll outgrow it soon so when I upgrade I'll go for the bulb I think. Seems much easier to control! Have heat lamps in with my dragons and much better. Thanks!


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