Which thermometer is correct?

[Lina]

Hi all,
So I've been measuring temps with the gun, about 2-3" off the surface, and it kept showing around 43C(109) under my 100W CHE. Now I finally got the dial thermometer with a probe, but I can only get it as high as 35C (95F) and that's after I moved the light even lower...
Now I measured with both at the same time and got the below results... How does it make sense? What to believe?
Also, I had 75W intense basking spot light, but Debbie started looking ill, so went back to CHE she came with... She's 8year old female, has MBD and just got clean off the parasites. I only have her a month so still trying to figure out things.

 

[lizardmom25]

Probe measures air temp, the gun measures surface temp.

 

[Lina]

So air temp is supposed to be 100F?

 

[CooperDragon]

That's a fairly big difference between the two readings. What is the ratio for your temp gun? That will read a fairly wide area depending on how far it is supposed to read from the surface but a couple of inches is usually about right. The probe may take 30+ minutes to start getting an accurate reading but will only read the temp at the probe site which is fairly small. If it isn't right under the basking light or if the basking light beam is too narrow it may affect that reading. If the temp gun is too close to the surface it can read hot spots (which you don't really want anyway) which could send the readings higher. I would move the temp gun around and try to get an average reading of the surfaces around the basking site and see if that better aligns with the probe reading.

 

[Lina]

My vet is amazing... He sent me a thermostat! Lucky Reptile Pro 2. I have it set up to 39C, and the probe is away from basking spot... Now thermometer reads (silver probe) 38C at the max... And temp gun... Well that thing still shows 50C...
I swear all these readings are like rocket science to me

 

[CooperDragon]

That's a good deal! At this point go with the reading on the probe or thermostat. Something is funky with that temp gun to have it be off by so much.

 

[Lina]

Something is funky with that temp gun to have it be off by so much.

I am guessing the fact its from eBay and cost me 12€?
For the moment thermostat and thermometer shoes reading up to 1C difference between each other... So I'll trust them.