My digi thermom vs my glass analog? lol

[dmoney87]

Im having a problem.

My digi thermometer (not cheap about 50$) is reading my tank at about 85* (mainly because I have gourmais fry) yet I also have a glass thermometer which is only reading 80* I find it hard to believe that one of them can be 5 degrees out. Is there something going on that Im not aware off? The digi temp sensor is attached to a suction cup halfway down on the back glass. While the glass one is free floating. Any advice suggestions would be greatly apprciated.

-davE

 

[jim692]

Easy way to test them is fill a glass up 3/4 with ice and then add water till full. Let it sit for a minute or two.
The temp of the ice water will be 32'F or 0'C. It's possible the thermometers are off a bit.
This will tell you by how much.
You may have temp fluctuations in your tank depending on the circulation currents.
The digital usually will be closer to true temp.

 

[dmoney87]

Easy way to test them is fill a glass up 3/4 with ice and then add water till full. Let it sit for a minute or two.
The temp of the ice water will be 32'F or 0'C. It's possible the thermometers are off a bit.
This will tell you by how much.
You may have temp fluctuations in your tank depending on the circulation currents.
The digital usually will be closer to true temp.

Well I did what you suggested and so far my glass thermometer is the winner. They have both been submerged in the ice water for about 2 min. The glas thermometer is reading 0*c on the button and my digi is reading 39.4* F .. wow so 50$ digi vs 1.99 glass thermometer so i guess sometimes technology really dosent pay off.. hmm well thats kinda crappy for me I guess lol.

thanks again Jim

-davE

 

[jim692]

No problem probably a bad thermocouple on the digi.
Try a cheap kitchen digi with a stainless steel shaft.
Expensive isn't always better.

 

[kreesdqban]

Wow Im gunna go test my digi now that I read this...

 

[neilanh]

Ive never found a digi that reads correctly. For absolute readings, I always use my glass thermometer

 

[missileman]

Same here, I wasted money on a digital and I never can get a accurate reading from it. The other day it was reading 45*, I know that is wrong. My glass thermometer read 77*

 

[jim692]

Check / change the battery before you throw it away.
A weak or flat battery can cause the readings to creep.
I've bought them off the shelf with bad batteries because they were in the store for so long.
I check mine every 2-3 months or so for that reason. It's the downside of the nice easy to read display.
Alcohol filled thermometers (glass/plastic) will not have this issue.

If you have a mercury filled thermometer (old) please be careful. It is a nasty substance.(I won't keep one in the house.)
If it breaks do not touch it. You can absorb it through your skin, and inhale the vapors through the lungs.
Do not clean it up with your bare hands, a broom, or a vacuum.
check this link for cleanup info.
Spills, Site Cleanup and Disposal | Mercury | US EPA

 

[kreesdqban]

just tested my digital therm. seems right, showed 0* C. I got it on ebay for $7. Seems like a good deal to me

 

[dmoney87]

Check / change the battery before you throw it away.
A weak or flat battery can cause the readings to creep.
I've bought them off the shelf with bad batteries because they were in the store for so long.
I check mine every 2-3 months or so for that reason. It's the downside of the nice easy to read display.
Alcohol filled thermometers (glass/plastic) will not have this issue.

If you have a mercury filled thermometer (old) please be careful. It is a nasty substance.(I won't keep one in the house.)
If it breaks do not touch it. You can absorb it through your skin, and inhale the vapors through the lungs.
Do not clean it up with your bare hands, a broom, or a vacuum.
check this link for cleanup info.
Spills, Site Cleanup and Disposal | Mercury | US EPA

You may be right with the batteries thing, Ill go pick some up tomorrow. Short of that I already contacted TOM the company that made my digi thermometer. I told them what was wrong and they flat out said send us the old one and we will send you a new one. So if its not the batts, Ill be sending it out. And yes if your talking about the red crap in the glass ones they are mercury filled. Ill be sure to handle with care. Thanks again

-davE

 

[jim692]

And yes if your talking about the red crap in the glass ones they are mercury filled. Ill be sure to handle with care. Thanks again

The "red stuff" in modern thermometers is an alcohol base with food coloring to make them easy to read. They are fine. The mercury ones generally have a silver look to them and will feel a bit heavy for their size. It's not that easy to get a real mercury thermometer now days. They aren't generally sold to consumers anymore. They are only made in China and India.