Thermometer Dilema

[RaveChild]

I replaced my digital thermometer today due to a broken thermal probe. Now my issue is that the new thermometer is giving a much lower reading than my original one, so I went and bought a third thermometer. This one, again, is giving a different reading. I also used my TDS meter to check the Temp. and it gives another different reading. So, from 4 thermometers, I am getting 4 different readings, which range from the lowest, to the highest reading, almost 9°F. How do I decide which is the thermometer that I should be using?

 

[cloak]

How does everything look? I use this one, but the sticker on the glass is pretty much the same. Top is the tanks temperature, bottom is the room.

 

[mixed_reefer]

I have been through the same thing in a way. I had 3 of the coralife digital thermometers and they all read different. I got a free thermometer from hello lights with my order a while back and it matched one of the coralife thermometers. Before i got ahold of two that match, i took an average of the 3 and went with that.

 

[xenon]

Welcome to the club. lol