thermometer questions

[donlankford]

I have two thermometer for my tank. One of the sticker ones that goes on the outside and one of the mercury stick thermometer that is inside the tank. Both give different readings. the sticker one reads 75 and the one inside the tank reads in between 79 and 80. I dont know which one to trust so if i can get some info on a reliable thermometer that will give accurate readings would be awesome. Thanks to everyone for the info

 

[bjohanson1234]

I would trust the one on the inside of the tank over the sticker on on the outside. Those are trying to read the temp through glass and also have the ambient air affecting them.

 

[donlankford]

thats what i was thinking just wasnt sure. thanks for the answer

 

[NanoReefer]

you can order a digital coralife thermometer that read up to 1?10th a degree. they only run about 15 bucks