Reptile & Amphibian Forums

Hi all

Recently I realized that my hygrometer in my pythons cage was a little off. So I bought another. I also have a digital one but its too big for the enclosure.

I tested to see which one is not working properly by placing them beside each other next to where the house thermostat is, watching the difference in humidity readings and comparing them to the house hygrometer. Whichever was not in line with the others is the faulty one right?

I was stunned to find that all of my hygrometers ( 4 in total) are giving me widly different readings. The house thermostat (also digital) says 40%, the digital one says 30%, one dial hygrometer says 20% and 2 other dial hygrometers say 55-60%!

The dial hygrometers are from exoterra and I'm not sure if they can be trusted.

How can all my hygrometers and my house thermostat be giving me seperate readings? Is there something about humidity physics I'm not aware of here or are all my meters busted?

(before you ask, my house thermostat's probe is where I tested all the equipment to make sure the playing field was even)

thanks all!

Nothing weird about it. Hygrometers purchased at pet stores or those you find in Walmart are garbage if you need accurate readings. At best, they can tell you if your humidity is basically low, moderate, or high but that is about it.

Be prepared to spend hundreds of dollars for a reliable unit if you want accuracy.

The dialogue in blue below was posted here not too long ago. Neat way to check hygrometers -

John,
You have found what I believe to be the most common reason for people thinking they have lower or higher cage humidity than they really do. Low cost hygrometers are notoriously inaccurate and many can easily be off by 10% to 25% depending on the brand. Unless you are willing to spend 150 to 200 dollars for a NIST traceable with a certificate, you can never be sure if your hygrometer is reading accurately. However, you can test your own quite easily to see if it is reading properly, and here is the procedure:

Kelly

-----
Mark

Thanks Mark that's very useful information.
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Jeremy Payne
JB Reptile

1.0 Snow "Kahl"
0.2 Triple Het Moonglow "Kahl"
0.1 Orange Tail Hypo Het Leopard
0.1 Double Het "Sharp" Snow
1.0 Ghost
0.1 DH Ghost
1.1 "Kahl" Albino
1.0.2 Hypomelenistic
1.3 Pastel Hypo
0.1 Anerthrystic
0.0.2 Normal

1.1 Morelia Clastolepis

I was able to calibrate all my hygrometers properly and compared it to a $2000 sling hygrometer that my buddy uses for his wharehouse. All bang-on.

If your meter does not have an adjuster just do the basic math and you'll get your humidity.