Crazy Hygrometer values

[Tugbay Yagci]

hello

i have been using my exo terra hygrometer for 3 days now and it shows %95 in my house. in the enclosures, it shows 100%.

i know the area i live in is very humid but can it be 95% or my hygrometer is out of order?

i exposed it to direct sunlight and it then showed %50, %45.

i keep my OBT and GBB tank bone dry as it is told in previous threads and iam afraid they wont live long if this device is showing the real humidity.

what do you say ?

 

[blix]

How is your ventilation in the house?

It's hard to tell if it's broken based on the description, the best way would be to get a different hygrometer to measure.

If you have a fan - try placing it some meters away from the enclosure, and keep an eye on the hygrometer.

 

[Tugbay Yagci]

we do not close the windows or balcony doors ever since it is very hot druing the day time. i measured in balcony and it still says 70-80. really weird.

do you know if these devices need any calibration upon purchase ?

i will try to get a different hygrometer.

 

[blix]

Those values are very high, I must admit. I don't think the hygrometer needs any calibration.

A different kind of hygrometer will definitely solve the mystery. If it turns out that it shows the same values, I would suggest that you should buy a dehumidifier

Usually they cost a couple of hundred dollars, some even cheaper.

 

[BrynWilliams]

is it an analogue hygrometer (the dial and needle type)? If so, be aware that they have a HUGE inbuilt error in them and are better used for indicating trends over time rather than trying to read the absolute value.

I would also agree that you try a second hygrometer, even a cheap one, to compare it with to see if they both are giving you similar high values.

 

[snakebytes]

Those hygrometers are crap. Just yesterday I found an old one (exo terra) I had that was put away into a storage box. Now I remember why. It was saying the humidity was 80-90% both inside and outside. I live in the desert of south New Mexico, so there is no way it could be that way. This time I threw it away for good.

 

[BrotherM213]

is it an analogue hygrometer (the dial and needle type)? If so, be aware that they have a HUGE inbuilt error in them and are better used for indicating trends over time rather than trying to read the absolute value.

I would also agree that you try a second hygrometer, even a cheap one, to compare it with to see if they both are giving you similar high values.

Very true. I had an anologe hydrometer in an incubator that seemed low (73%) compared to the moister I put in. So i tried my digital to double check as sure enough it showed it to be (85%).

 

[Nomadinexile]

Hygro

So,... 100%? I don't think it's ever 100% unless you are in a rain forest swimming in the river in the rain. Without air conditioning, even in the tropics, you will be around 75% humidity unless it is raining or just after, or you have a koi pond in your living room with a heater underneath it.

There are accurate hygrometers. I did buy one (little round brass thing)
for about $6-$8 that seems to be relatively close. But to get a good Hygrometer, you will have to spend a little bit.

One option for you, is to put your hygro outside (for a minimum 1-2 hours to let it reset values) and check it with weather channels humidity index for your location. You will then know if it's close. If you do this a couple of times and you are always the same, or 5 points to high, you know that. If one day it is 5 points over, the next day 10 under, etc, then it's broken. If you check it well, you can walk into store and go, "this doesn't work" and get you cash back.

Hygrometers don't bounce well. Accurate readings require that the needle rotate freely. If anything gets messed up along "bearing", you won't be able to get good reading. If there are scratches on the "bearing", or it somehow wasn't set right, or machined right, etc. So Don't Drop Them!

Peace, Ryan

 

[Sarcastro]

those things are complete junk..do yourself a favor and get yourself a good digital thermo/hydro...my roommate had may of these in his dragon enclosures that read 90-100% all the time and we lived in the Arizona desert
...god how i miss that place

 

[Memento]

There's an easy way to check if the hygrometer calibration is accurate:

Mix 1/2 cup salt with 1/4 cup water in a cup, and put the cup in one of those resealable freezer bags with the hygrometer (don't get any salt mix on the hygro). Seal the bag and let the whole thing sit for about 10-12 hours, out of the sun at room temp.

When the time is up, the hygro should read 75% while inside the bag. If it doesn't, either adjust it (if it's adjustable), or just make note of how many percentage points it's off so you know how much to add/subtract when you take cage measurements.

This works for both digital and analog models. I usually junk any of them that show more than 6%-7% off the mark.

 

[Stan Schultz]

... i have been using my exo terra hygrometer for 3 days now and it shows %95 in my house. in the enclosures, it shows 100%. ...

You should have spent the money on another tarantula instead! Read the following threads.

http://www.arachnoboards.com/ab/showthread.php?t=145610. Pay particular attention to posting #27. It's mostly about temperature and thermometers, but the same principle holds for nearly all hygrometers as well.

http://atshq.org/forum/showthread.php?t=14286, posting #9

http://www.arachnoboards.com/ab/showthread.php?t=146774, posting #14

http://www.arachnoboards.com/ab/showthread.php?t=145819, posting #6

http://www.arachnoboards.com/ab/showthread.php?t=111523, posting #9

Now, out of curiosity, why are you worried about relative humidity anyway?

 

[Skullptor]

I have come to the place where I believe Pikaia absolutely on this topic. I used to be one who over monitored my spiders, and got caught up in that whole "environment creation" mentality.

I now have two basic rules with regards to enclosure ambiance: Avoid direct sunlight- and don't let the temps fall below, or exceed a comfortable room temperature (for me that is).

They are thriving and I have less work and get to spend more money on T's like Pikaia suggested.

 

[Stan Schultz]

There's an easy way to check if the hygrometer calibration is accurate: ...

This works for both digital and analog models. I usually junk any of them that show more than 6%-7% off the mark.

Memento, you're the first one I know of who's given a reasonably good description of how to calibrate a hygrometer. Thank you. :clap: :worship:

Having said that, those of us who are obsessive, compulsive, and anal retentive will have to point out that this is actually only a one point calibration. Much greater accuracy can be obtained with a two point calibration with the second point being at some widely different rH. What salt might we use for the second point? If not a salt, what other method?

BTW, the Devil's advocate will hasten to point out that since most of the rH-s that we use are in the 75% range (±15%), and most tarantulas are so resilient and adaptable that it makes little difference, your calibration is probably "good enough for the guys/gals we go with" anyway.

LORD HAVE MERCY! Now I foresee everybody racing into the kitchen to do an accuracy check on whatever their favorite hygrometer might be, and a resulting 45,000 postings here regarding how good/bad/indifferent each is and how to proceed with correcting it or compensating in some fashion.

AS A PREEMPTIVE STRIKE: IT REALLY DOESN'T MAKE ANY DIFFERENCE! USE A WATER DISH. COVER THE OPEN PART OF THE CAGE WITH PLASTIC FOOD WRAP. STOP OBSESSING! GET ON WITH YOUR LIVES!

[End of rant]

 

[Memento]

I tend to agree. The widely used salt test is the "good enough" household method. If someone really wanted a two point calibration, they could wrap the hygro in a very damp (not dripping) paper towel and check for ~98%, but it's overkill. It's also useless to try if the hygrometer is reading too high to begin with.

I'm with Pikaia on the general hygrometer issue, though. As long as you're providing the correct living conditions regarding water, temperature, substrate and ventilation, you don't really need one. I've only had to use them with certain fragile amphibians in a controlled setting, never with home pet arachnids or other arthropods.

 

[BrynWilliams]

Well I've learned something today, I'm gonna try it just because I have never

I'll probably also see if my housemate's exo terra analogue hygrometer is better than my alternative brand one. Should be interesting. Thanks for educating me memento

(for those wondering we only have the hygros for the tree frogs and his gecko)