Thermostat not equal to the thermometer

Ok so...before I used to use just a dimmer, but I went ahead about a thermostat that I've seen some people suggest. I bought some of the prob thermometers to double check the temperature.
The gauge on the thermostat says 78, the gauge on the thermometer says 90. It feels warmer then 78. And the thermostat hasn't moved up at all. I've got it set for 90, but it's just not getting up there according to his gauge.

For right now I unplugged the thermostat, worrying that it's trying to push the UTH up higher when it doesn't need to. My mate will be here all day to monitor temperatures, so she can adjust it if it gets too warm, but right now even without the thermostat it's hanging at 90. Anyone have any suggestions or problem like this before? I'm using/trying to use one of these: http://www.amazon.com/Hydrofarm-MTPR...dp/B000NZZG3S/

Where are your probes (both the thermostat and thermometer)?

the Hydrofarm isn't very accurate at all, that combined with the inaccuracy of cheap digital thermometers and you can get some pretty big discrepancies.

Location of both probes?
I never trust the numbers on the sticker at all;)

Both of them are directly in the middle of the hot side, on the ground. I've got just about an inch of space between them so they don't touch each other and something effects it that way.

Are they on top or under the substrate? Where is the thermostat probe? I would move the thermostat probe to the outside of the cage (if you haven't already) and then adjust it until your thermometer in the tank reads about 90*.

At the moment, I don't even have the thermostat on. The thermometer is hanging at 90 without it. Although, I know as it gets colder it won't. And they're both at the bottom.

What type of thermometer are you using, are there any other heat sources in the cage? I would question the thermometer readings.

What kind of heat mat are you using? It should be getting a lot hotter than 90º on its own.

just an Ultratherm UTH heater is being used for heat. Nothing else. I'm not sure what kind of thermometer I've got. I don't see a name on it and I've already tossed the packaging.

It sounds like there are three things the first being ultratherms are self regulated to not get over 100º in an 80º room ambient temp. They in cooler rooms will not even reach this.

The hydrofarms are very very poor accuracy they are supposed to be with in 2ºC of correct (about 4ºF up or down from correct) long story but I have a number that I have been paid to evaluate. I think there is 3 in the first batch and 6 in the second. 3 of them are beyond the 4º mark from correct. They all read high ranging from 1.3ºF to 5.9ºF from correct. There is likely an error with the T-stat.

Digital thermometers come it two flavours cheap and accurate. Most cheap (sub 100$) have an accuracy of +/-2ºF for correct and with age this can decline more.

It is possible your thermometer is faulty or that is is incorrect one direction say 2º low and the hydrofarm is 4º high that would mean the hydrofarm set to 90 is actually 86º if the thermometer is 2º low 86º would read as 84º that is if everything is in the specs! It is easy for both to be outside specs too.

It sounds like both are an issue to me Personally I would suggest if you choose a hydrofarm a correct reliable thermometer (Traceable with less than 1ºF +/- error) is a must. Sadly the price of such a tool is more than the savings on the thermostat compared to a better reptile specific t-stat.

Alright so I have the same issue as the OP. Thermostat says 98 hydro farm says 96. Set to go off at 93. Surface temps though (measured by good quality IR gun) are from 88 to 93 (93 under his hide). Given this info what would you recommend I set the hydrofarm at?

Thanks

Edit: I have the zoo med UTH

Edit2: I have about and 1/2 to 3/4 inch of apsen.

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Originally Posted by NewBP

Alright so I have the same issue as the OP. Thermostat says 98 hydro farm says 96. Set to go off at 93. Surface temps though (measured by good quality IR gun) are from 88 to 93 (93 under his hide). Given this info what would you recommend I set the hydrofarm at?

Thanks

Edit: I have the zoo med UTH

Edit2: I have about and 1/2 to 3/4 inch of apsen.

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Why would you change your settins if your surface temps are good??

Just ignore what the Hydrofarm says buy a good thermometer and use this to set it.


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https://www.fishersci.ca/coupon.do?cid=200619

Just got a few of these for my work they look quite good so far.


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Quote:

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Originally Posted by kitedemon

https://www.fishersci.ca/coupon.do?cid=200619

Just got a few of these for my work they look quite good so far.


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Yeaaah, for six-hundred dollars they better get that temperature down to the smallest point.

I know no two thermometers are going to read the same, and there's going to be some inaccuracy between the two. But I didn't expect an inaccuracy of 20 something degrees. Now, they're hanging around in the same place almost. Sometimes with 5 degrees differences between each other. Am I going to keep the set up the way it is? Probably not. But a six-hundred dollar thermometer is a bit out of my reach right now, so I'll just have to scour through other forums to see what others suggest or use I guess.

With the error rate of hydrofarm and the error rate of a typical digital 10º difference is not out of possibility. The problem with hydrofarms is the if it is working correctly you could set it at 90 and it could actually be from 86-94º. Add swing, regular thermometer error and you can easily double this. As I stated earlier that it is likely both hydrofarm and thermometer that are off one one direction one the other.

The truth is that helix herpstat ecozone herpkeeper and VE all have accuracy of less than 1ºF these are actually cheap accurate thermometers the fact is is also a great thermostat is just a bonus.

When you have no way of knowing what is right you have no way of knowing what is wrong.

Quote:

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Originally Posted by kitedemon

The truth is that helix herpstat ecozone herpkeeper and VE all have accuracy of less than 1ºF these are actually cheap accurate thermometers the fact is is also a great thermostat is just a bonus.

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I know. I'm looking into some of these. I just didn't think about these right now, because I only have one little guy, with another on the way. And plenty of people have recommended the one I have on the forums, so I just figured until we got a bigger set up it'd work.

I see you point I don't truely agree but I get the descision.

The best way to cheaply find a reasonably accurate thermometer is to buy a bunch of cheap ones (3 min and 5+ is better) lay them all out away from drafts and check them against each other. Typically some will read the same these are •likely• close to accurate then you have a base to figure out where what is off. The other option is also cheap but a bit more complicated see if you can find a liquid crystal thermometer that is in one degree or better steps and place this on a surface in the reading zone and then your hydrofarm probe and your other T-stat check them against the LC one. They often (usually) are accurate to one half degree. This will (hopefully) show you correct so you can se if your thermometer is off or the probe or both and how much.