Hygrometer accuracy
Login
User Name
Password   


Registration is FREE. Click to become a member of OrchidBoard community
(You're NOT logged in)

menu menu

Sponsor
Donate Now
and become
Forum Supporter.

Hygrometer accuracy
Many perks!
<...more...>


Sponsor
 

Google


Fauna Top Sites
LOG IN/REGISTER TO CLOSE THIS ADVERTISEMENT
  #1  
Old 04-08-2017, 04:27 AM
MiniatureOrchids MiniatureOrchids is offline
Jr. Member
 

Join Date: Mar 2017
Location: London
Posts: 28
Hygrometer accuracy
Question Hygrometer accuracy

Hey all, tricky question for you. What hygrometers do you use to track humidity in your terrariums?

Reason I ask is that I bought a reasonably cheap hygrometer on Amazon, and we've been using it for 6-12 months. It often said that the humidity was > 90% despite moss etc feeling a bit dry. Last week, I ordered a new Hygrometer (with a wired probe) and it was reading about 20% lower than our original one, which indicates that all the time we thought the humidity was in the 90s, it was probably in the 70s.

So, after a bit of googling, I tried the salt test last night. I put a bottle cap of salt with some water, along with the hygrometers, into a sealed container for 12 hours. In theory, the humidity should stabilise at 75% and you can get an idea of the hygrometer's accuracy and then compensate when reading it.

But now, the hygrometers (which are in the tupperware tub with the salt) are saying 72% and 74% respectively. The latter reading is the one that was showing as 99% previously.

So it seems like they're both approximately correct around the 75% mark, but diverge dramatically once humidity increases.

So what does one have to do to get an accurate meter? Should I stick with an analogue meter instead? Any recommended and well-respected brands to try? It's no good trying to keep a humid environment for the orchids and moss if we think it's at 90%+ and actually it's at 70% - or vice versa!!!
Reply With Quote
  #2  
Old 04-08-2017, 06:43 AM
Ray's Avatar
Ray Ray is offline
Senior Member
 

Join Date: May 2005
Location: Oak Island NC
Posts: 8,112
Hygrometer accuracy
Default

First, assuming you have a bit of air movement in the chamber, the difference between 70% and 90% RH is probably of little consequence to your plants.

But if you just have to know, get a certified hygrometer.
__________________
Ray Barkalow, Orchid Iconoclast
KelpMax™ - the Best Root Stimulant Available: shop.firstrays.com
Free Shipping of stock items in the US! (see terms & conditions for details)
Reply With Quote
Post Thanks / Like - 1 Likes
Likes MiniatureOrchids liked this post
  #3  
Old 04-08-2017, 06:58 AM
MiniatureOrchids MiniatureOrchids is offline
Jr. Member
 

Join Date: Mar 2017
Location: London
Posts: 28
Hygrometer accuracy
Default

I guess my main concern is with the general lack of accuracy, can I trust them to tell the difference between 40% and 80%, which would be more critical.

Do you have any links to certified units (otherwise I'll Google).
Reply With Quote
  #4  
Old 04-08-2017, 01:50 PM
Ray's Avatar
Ray Ray is offline
Senior Member
 

Join Date: May 2005
Location: Oak Island NC
Posts: 8,112
Hygrometer accuracy
Default

Google is your friend
__________________
Ray Barkalow, Orchid Iconoclast
KelpMax™ - the Best Root Stimulant Available: shop.firstrays.com
Free Shipping of stock items in the US! (see terms & conditions for details)
Reply With Quote
Post Thanks / Like - 1 Likes
Likes MiniatureOrchids liked this post
  #5  
Old 04-08-2017, 05:39 PM
Salixx's Avatar
Salixx Salixx is offline
Senior Member
 

Join Date: Apr 2016
Zone: 5b
Location: Lakes Region, NH
Age: 30
Posts: 483
Hygrometer accuracy Female
Default

I think we may have bought the same cheapo off Amazon. I have one that is always saying the tank is in the 90's but my home hygrometer says 70's if I put it in the tank. I actually stopped looking at it since the plants are all fine.

In another enclosure, I use an analog Exo Terra hygrometer that's a lot more accurate. Not exactly low profile, but I can hide it in there. If you are looking for a cheap option, it works well.
Reply With Quote
Post Thanks / Like - 1 Likes
Likes MiniatureOrchids liked this post
  #6  
Old 04-08-2017, 09:45 PM
estación seca's Avatar
estación seca estación seca is online now
Senior Member
Hygrometer accuracy
 

Join Date: Jun 2015
Zone: 9b
Location: Phoenix AZ - Lower Sonoran Desert
Posts: 6,885
Hygrometer accuracy Male
Default

An engineer friend tells me they're not very accurate under most circumstances. I think the condition of your mount moss and orchid roots tells you more than the hygrometer dial.
__________________
It's a dry heat.
Reply With Quote
Post Thanks / Like - 1 Likes
Likes MiniatureOrchids liked this post
  #7  
Old 04-26-2017, 01:50 PM
jdusablon jdusablon is offline
Jr. Member
 

Join Date: Apr 2017
Posts: 3
Hygrometer accuracy
Default

Don't know how much this helps, but the DHT11 sensors are very cheap and very accurate, just not fast at updating. I suspect, however, that you're looking for a standalone unit.
Reply With Quote
Post Thanks / Like - 1 Likes
Likes MiniatureOrchids liked this post
  #8  
Old 06-18-2017, 07:36 PM
dethswatch dethswatch is offline
Jr. Member
 

Join Date: Jan 2016
Posts: 5
Hygrometer accuracy
Default

This is super-accurate:
Amazon.com: BUKE MS6508 Digital Humidity Temperature Meter Ambient Temperature Relative Humidity Measurement Data Hold Data Logging: Kitchen & Dining

It uses a Sensirion sht-75 sensor- you can google for the "datasheet" and see exactly how accurate over a range of temps and H's.

It'll last a coupe days on fresh batteries if you want to leave it on and give you high and low temps/H's too- so that you can get a clear idea of your ranges.
Reply With Quote
  #9  
Old 06-19-2017, 10:13 AM
MiniatureOrchids MiniatureOrchids is offline
Jr. Member
 

Join Date: Mar 2017
Location: London
Posts: 28
Hygrometer accuracy
Default

In the end I got one of these: Digital Hygrometer Humidity with Remote Probe 20-90%: Amazon.co.uk: Pet Supplies
Tested it with the salt method, and compared it against two other hygrometers I have, and it looks like they're all consistent and reasonably accurate.
Reply With Quote
Reply

Bookmarks

Tags
humidity, hygrometer, hygrometers, reading, salt


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
digital hygrometer VickiC Beginner Discussion 2 02-24-2009 08:28 PM
Calibrating a hygrometer (used ofr measuing humidity) Paul Terrarium Gardening 1 07-19-2008 07:56 PM

All times are GMT -4. The time now is 12:33 AM.

© 2007 OrchidBoard.com
Search Engine Optimisation provided by DragonByte SEO v2.0.37 (Lite) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Feedback Buttons provided by Advanced Post Thanks / Like (Lite) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Clubs vBulletin Plugins by Drive Thru Online, Inc.