Verify that your Hygrometer is correct

The first thing I think anyone should do is to test their hygrometer (humidity measuring device) to make sure it is accurate. I often wonder how many times people have unexplained deaths in a tank that has "perfect" conditions.

More often times than not, the analog (or dial type) gauges are quite inaccurate. It is easy to detect when you are getting condensation on the walls of your tank and your hygrometer is reading 75%, it is fairly obvious that something is amiss. But may not be so easy for a beginner when the situation is reversed.

Here is a simple test you can do to make sure your gauges are giving you accurate readings.



1. Get a bottle cap of any kind/any size. Fill it with regular table salt. Then
add a few drops of water on the salt. DO NOT add too much water. The salt
should only be damp, not wet enough to dissolve. You are trying to make a "saturated solution"

2. Put the bottle cap and your hygrometer in a plastic zipper loc freezer bag. Seal the bag and wait about 6-7 hours. You can also use any air tight container-such as the type used for storing food (which is what I use) or a wide mouth mason jar. The important thing here is that it is air tight.

3. The humidity inside the bag will be 75% after 6-7 hours.

Why? Because when salt and water are in a saturated solution at equilibrium the resultant humidity is 75%

You may elect to keep your analog gauges and make a mental note of the difference or change it if you have the type that can be calibrated. Or you may want to invest in a digital one. I also would perform this test on your digitals to make sure they are accurate as well.

 

Worthy of the library! Bravo Kupla. If you want, Might as well copy it to the library.

Cappa

 

Excellent, I have been rotating a battery operated temp/humid digital and this would have been alot easier to test all my dial ones at the same time.