Which one is right?

[stickx911]

3 of basically the same thermometers, measuring the exact same spot (probes banded together) and 3 different numbers. :unsure:

I was trying to make sure my W/c water was close in temp with tank, and just found it funny that they are all different. I know they're not crazy off, but it is more than a degree or two between and almost 4 degrees between the two extremes.

Edit:

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picture might help

 

[kilralpine]

All are mercury thermos?

 

[heathlindner25]

UN band them and try, might be getting a weird readout ,so close together

 

[stickx911]

I originaly had them in different places of the 4 gallon jug and I got even more spread out results. (4g mixing bucket with a 300gph powerhead pointing up)

 

[heathlindner25]

Nutty,

 

[kilralpine]

I would invest in a cheap 10$ lab grade mercury to get a base line. Then use whichever you find closest or most reliable; these types of thermos are kind of well known to be +-1 degree off.

 

[ralph atl]

Calibrate it if it goes to 32, by 50/50 ice and water bath....that's how I calibrate mine.

 

[lilrobb]

mysterybox;789348 wrote: Calibrate it if it goes to 32, by 50/50 ice and water bath....that's how I calibrate mine.

Don't try this with electronic probes - they're ALL known for a ridiculous spread 20degrees off the calibration point. It has to do with how they measure temp, somewhere was a thread.

 

[ralph atl]

Well, that would be useless....then...

I use a thermocouple for food temps on the grill and oven....I love my lamb chops at 140.....my tank at 78, and calibrate probe in 50/50 ice water bath....

 

[chris s]

Actually they may all be correct according to coralife. They are supposed to be accurate +/- 1.5F. Your spread from high to low is less than 3 degrees so if the actual temp is in the middle they are all within the limit.