Hygrometer accuracy


Turbonetics

Senior Member
Feb 19, 2009
2,701
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#1
Hi,i have been using the Aipo 48EX dry cabinet with digital readings.
i set it to 44% humidity and it usually hovers between 44-45%.
recently i bought a standalone Hygrometer.
i placed it in my drycabinet for 1 day and it hovers between 56-58%.
both readings doesn't tally and the difference is quite huge.
anybody can advise on which should be the correct reading?
thank you.


http://flic.kr/p/bfgA3t
 

Last edited:

Achim Reh

New Member
Nov 1, 2011
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#2
the only way to find out which measurement is correct , is, to get ( or borrow) a calibrated hygrometer.
However, please make sure both measure the same , for example, does one of them have a temperature compensation ?
 

Turbonetics

Senior Member
Feb 19, 2009
2,701
6
38
#5
i did the salt test and my standalone hygrometer shows 75%.
can i confirm that my dry cabinet hygrometer is not accurate?
 

Dec 23, 2010
358
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#6
Betweent 45-55% is ok setting as long as fungus cant thrive. Not sure if it so necessary to be so military precised? I set my dry cab at 50%.
 

Octarine

Moderator
Staff member
Jan 3, 2008
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Pasir Ris
#7
i did the salt test and my standalone hygrometer shows 75%.
can i confirm that my dry cabinet hygrometer is not accurate?
You ask us whether something in your dry cabinet is not working correctly? Your test shows that your stand alone hygrometer works well, that's all what your test shows. Everything else is assumption. Use the stand alone device then.
 

Dec 11, 2010
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#8
Octarine said:
You ask us whether something in your dry cabinet is not working correctly? Your test shows that your stand alone hygrometer works well, that's all what your test shows. Everything else is assumption. Use the stand alone device then.
it does suggest that the one in dry cab is nt accurate, but perhaps shld tk out n test n calibrate?
 

Octarine

Moderator
Staff member
Jan 3, 2008
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Pasir Ris
#9
it does suggest that the one in dry cab is nt accurate, but perhaps shld tk out n test n calibrate?
Your decision :) Curious as I am I would try it. But these cheap mass products my not be prepared for being calibrated, you just need to know about the offset.
 

Dec 11, 2010
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#10
Octarine said:
Your decision :) Curious as I am I would try it. But these cheap mass products my not be prepared for being calibrated, you just need to know about the offset.
oh.. haha.. anyway if it's below 45% i'm nt too worried since the other thread showed that lub n plastic wun dry..
 

ed9119

Moderator
Staff member
Mar 11, 2002
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Singapore
www.walkeast.com
#11
i did the salt test and my standalone hygrometer shows 75%.
can i confirm that my dry cabinet hygrometer is not accurate?
.... you could do that test with a few other sodium variants with different hygroscopic values ..... then, can really confirm
 

An drew

Senior Member
May 27, 2005
3,920
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#12
I just want to say that if you set your cabinet to 45-50% then you are cutting it close. I had a lens with fungus in cabinet with the meter showing 50%. I think the meter had gotten slightly out of calibration over time.
Now I set one cabinet to 35% and another to about 40%. And I also remove the front lens caps.
 

NicePic

New Member
Dec 13, 2011
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#13
I have 2 dry cabinets and bought 4 external hygrometers recently. They all show about the same readings (about +15% more than dry cabi readings).
I always set my dry cabinets to 45% and all my external hygrometers shows about 60%

My question:
The relative humidity in sg is above 80% so will there be problem if I do the salt test? (unfortunately I cannot afford air-con at home)
I have one in a ziploc bag now... waiting for inspection tomorrow.
 

Last edited:

David Kwok

Senior Member
Aug 23, 2008
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www.flickr.com
#14
.... you could do that test with a few other sodium variants with different hygroscopic values ..... then, can really confirm
Correct me if I'm wrong, I believe pure sodium chloride will do, it's based on lab tests that shows at different temperatures, sodium chloride slug maintains at near 75% RH.
 

#15
Turbonetics said:
Hi,i have been using the Aipo 48EX dry cabinet with digital readings.
i set it to 44% humidity and it usually hovers between 44-45%.
recently i bought a standalone Hygrometer.
i placed it in my drycabinet for 1 day and it hovers between 56-58%.
both readings doesn't tally and the difference is quite huge.
anybody can advise on which should be the correct reading?
thank you.

http://flic.kr/p/bfgA3t
Hi, I have the same model as you and the standalone hydrometer shows about the same value as yours when the cabinet meter set to 44%.
I did a salt test calibration with my analogue hydrometer(the digital hydrometer seems pretty accurate) and I now have to set the cabinet meter to 30% to achieve the RH45-46% reading from the 2 hydrometers in my cabinet :(
 

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