Thermometers - Which one is best to use???

[LittleChicks4Me]

Hello,
I Need some help... I will be incubating eggs is March. Incubator all set. Tested and retested BUT which thermometer is right?

Regarding thermometers: Each seems to register a different degree..

Accu-rite digital thermometer with humidity check: temp shows 97 degrees/35 humidity - will fix humidity once I get an accurate thermometer.

Small plastic Springfield red alcohol thermometer shows about: 99-100

Cooking thermometer probe: 100

Purchased a vintage Rexall Clinical Thermometer with mercury on ebay this week: 104


Right now, the readings are..listed above. According to the Clinical thermometer (104 degrees in the air circulating incubator, I would have killed any eggs by going with them..

Is the Clinical thermometer the accurate reading?

Help I don't want to kill the hatching eggs I have purchased..soon to be shipped in a few weeks. I will not set any eggs till I have the right thermometer.

I keep buying thermometers.. lol to find each one is different... sigh...

Thank You!!!

Also, How do I calibrate the clinical thermometer?

 

[lazy gardener]

You have stumbled upon the eternal curse of incubation. Inaccuracy of thermometers and hygrometers is IMO the main reason for incubation failure. I use an old fashioned mercury bulb type thermometer. It's about 35 years old. I calibrate all of my other thermometers against that one. The big issue is, even if you calibrate a standard thermometer with the ice water trick, it may be accurate at 32*, but that doesn't mean that you won't get some drift of accuracy as you approach 100*F. I've even been tempted to take my hand full of thermometers with me to my next Dr's appointment, and check a bulb type thermometer against their digital one... but then, I'd be stuck, explaining to the people in the white suits, and I might just end up with a diagnosis other than the problem I went for in the first place.

 

[LittleChicks4Me]

Ok LG, So the Vintage Mercury Clinical thermometer is the correct temp?

I inserted the bulb in into my foam incubator, at the height my eggs would be at inside, till it is within the moving air. With the rest of the thermometer sticking out.

So I should back down my incubator temp from 104 to 99.5, on the mercury thermometer?

*** Saturday 4am - Just started a new test with the old mercury thermometer, placed in inside the incubator in it's box as my holder.. Now I will watch it and the probe cooking thermometer. Ignoring the red alcohol and digital for temp.
Digital just for humidity. Which could also be off....

 

[Egghead_Jr]

Use an oral temp thermometer to set incubator temp and calibrate the Accurite temp. You likely already have one in your medicine cabinet.

You can do a search for salt test to calibrate the humidity.

Salt Test:

Fill milk cap with table salt.
Drip water in until salt turns to paste, like saturated sand not a slurry.
Put the cap and hygrometer into a plastic sealable bag and wait 6 hours or more until humidity stabilizes.

The humidity in the bag will be 75%, mark on tape and afix to hygrometer how far off 75 it reads. By adding that number every time you take a reading you'll always know the correct rH%. ex. reads 68 end of salt test, write -7 on tape.

 

[LittleChicks4Me]

Use an oral temp thermometer to set incubator temp and calibrate the Accurite temp. You likely already have one in your medicine cabinet.

You can do a search for salt test to calibrate the humidity.

Salt Test:

Fill milk cap with table salt.
Drip water in until salt turns to paste, like saturated sand not a slurry.
Put the cap and hygrometer into a plastic sealable bag and wait 6 hours or more until humidity stabilizes.

The humidity in the bag will be 75%, mark on tape and afix to hygrometer how far off 75 it reads. By adding that number every time you take a reading you'll always know the correct rH%. ex. reads 68 end of salt test, write -7 on tape.

I just bought the old type glass thermometer with the mercury in it. For accuracy.. So I should use that and forget the other thermometers?

 

[Egghead_Jr]

I like the digital in incubator because reading it is so easy and has combined humidity. I only keep a temp/hygro cigar humidor model in the incubator. It reads a degree low but alerts me to changes then I get the oral thermometer and do a slight adjustment. The digital easily reads and shows temp is steady and with salt test accurately reads humidity which is important.