Hygrometer - suggestion?

[vincent 121]

Hello everyone,

I need to buy 2 hygrometers for my terraria.

There are plenty around, from very cheap to reeeeeeeeeally expensive. But the issue is that most of them are designed to measure the humidity in houses/appartments, which is far from what we expect in our terraria (hopefully, otherwise you either have issue in your house or in your growing set-up!)

So, do you recommend any model that is precise at high humidity levels?

Cheers

Vincent

[Prompt 20]

Hello Vincent, hygrometers measure the humidity from 0 to 100%, I have seen no hygrometers that measure different moisture.

We growers do not need professional hygrometers, most of us, use digital hygrometers low cost found in any oriental shop, supermarket or electronics stores.

I use a digital thermometer/hygrometers with probe, paid 8 euro.

Prompt

[Richard Bunn 443]

I just use a cheap non-digital one from ebay that is built in to the thermometer. You can see it as the smaller dial here http://www.ebay.ie/itm/Indoor-Outdoor-Hygrometer-Wet-Humidity-Thermometer-Temperature-Temp-Meter-Gauge-/331051423571?pt=UK_Home_Garden_Weather_Stations&var=&hash=item4d1433d753

[pmatil 21]

I have some experience on different hygrometers. Some time ago I used Lucky Reptile Hygrometer Deluxe Pro meters (http://www.luckyreptile.com/products/145/en/pid1,2$pid2,3335$pid3,7773728/products.html). I still have one in another terrarium.

For my main terrarium I have Lucky Reptile Humidity Control Pro 2 which is a controller but has hygrometer too.

And finally I recently bought an analog humidity gauge (Lucky Reptile precision hygrometer).

The problem is the very high humidity of terrariums. Usually, when humidity increases above say 80 %, hygrometers start to display an offset to the real humidity. For example when comparing the controller's humidity value to my reference meter (accurate) the difference is +12 % to +20 %, eg. when the controller displays 95 % the real humidity is around 75 % - 83 % and so on. At the same time the analog gauge shows between 75 % and 80 % humidity. So what is real?

To sum it up: almost every (cheap) meter shows too much or too little at the top of the scale. Also the humidity displayed depends on the atmospheric pressure. Luckily most CPs don't require a precise humidity as long as it's high.

I'm still in progress to compare different meters to my reference meter (non-commercial self-made) so I currently don't have a good recommendation. Basicly the meters sold for terrariums SHOULD be ok. Good luck.

[Pietro"Pedro" 2]

I have this

http://www.amazon.it/TempTrend-Stazione-metereologica-radiocontrollato-Importato/dp/B001ARJ27O/ref=pd_sim_sbs_hg_1

[snowwy 59]

I use Exoterra hygrometer. It was a bit expensive but it has worked great 2 and half years now.

[Ian_P 29]

I used to use one similar to this in my vivarium, measures temp and humidity, http://www.ebay.ie/itm/TERRARIUM-VIVARIUM-DIAL-THERMOMETER-HYGROMETER-REPTILE-SELF-ADHESIVE-/261112210476?pt=UK_Pet_Supplies_Reptiles_Spiders_Insects&hash=item3ccb80242c

[vincent 121]

Thanks for the answers.

I fully agree with pmatil: even though they are all supposed to measure up to 100%, the range at which they are precise usually does not reach more than about 80%. See an example here in the product description:

http://www.aliexpress.com/item/ROUND-NEW-Indoor-outdoor-Thermometer-and-Hygrometer-Wall-anymetre/746374056.html

The measuring range for humidity: 0% to 100%

But the humidity accuracy is ± 5% (40% ~ 80% of)

The main issue is: how to check if they are precise or not!

[pmatil 21]

Yes that's the problem. Even with my precision hygrometer the accuracy between 20-80 % is +/- 1.8 % but between 10-20 % and 90-100 % the accuracy is +/- 2-4 %. Better, but not perfect.

[North West Neps 645]

I bought one of these > http://www.ebay.co.uk/itm/330511397387

I placed it on my bathroom windowsill where my Neps reside. I became curious of how accurate it was was after reading that they can be +/- 5% inaccurate.

Soon after, i ordered a second one for another windowsill when my Nep collection started expanding rapidly. But first of all, i placed it side by side with my first (identical) hygrometer in the bathroom while i was waiting for a nice hot bath to run one evening. They displayed a difference of 4 degrees C between them, and a difference of 6% RH constantly. Combine this with the +/- 5% inaccuracy and they become practically worthless, especially where the forthcoming winter night time temps could mean life or death for some of my Neps

I'll avoid the cheap ones in future !

Edited November 20, 2013 by Welshy

[vincent 121]

Hi,

Actually, I've heard that the inacuracy can reach much more than 5%. In reality, it seems it's more something like 10-15% at high humidity!

I've ordered 2 different ones and I'll let you know after I can perform some tests.

[pmatil 21]

Yes, 10-15 % error is correct. For my humidity controller (lucky reptile) the inaccuracy is specified as +/- 5 % BUT the sensor element inside has specs of at least +/-7 % at high humidity and I've measured an error of about 10-15 %. So I have to adjust the humidity 10-15 % higher so that the real humidity is correct. Very annoying.