I figured it was time to recalibrate some of my hygrometers, so I started a salt test.
Normally, I just use plain, old table salt, but we were out of that, so I used some sea salt.
Results should be the same, right?
I have 2 tupperware containers, each has 3 hygrometers in it. Right now, they've been in there for a little over 48 hours.
Well, here's what's happening.
Using the corrections I had marked on the hyrometers from the last time:
The readings in container #1 are 70%, 70%, & 69%
The readings in container #2 are 70%, 69%, & 71%
for an average of 69.8%
Thoughts?
Is it because I used sea salt instead of regular table salt?
As far as readings go, I dont really see a problem (The average is ~70%). This is why you do a calibration, so you know how far they are off.
What you are noticing is because your hydrometers probably use capacitive sensors. They're great, but over time are only going to be accurate within +/-2% assuming you calibrate them. Anyway, they are prone to drift and aging which leads to the kind of things your seeing here (Even with calibration).
The other thing to keep in mind is that different salts will give different results. I.E., Table Salt (Sodium Chloride) with distilled water should result in ~75% humidity. Something like Potassium Sulfate (K2SO4) which is still a salt, with a bath of distilled water is ~96%. Bottom line, using Sea Salt probably isn't helping you, but i feel the calibration is still good enough. Sea Salt Vs. Table Salt is very close chemically.
Hope that answered your question...
The thing is, 2 of the hygrometers are the ones that you can adjust the calibration. The other 4, I have marked them with how much they are off.
Part of me likes that all 6 are still consistent with the last time I did the calibration but now all 6 seem to be off an additional 5%. Something seems wrong to me. I don't see how statistically all 6 could be off the same additional (5%) amount.
I'll have to get some plain table salt to check again.
Table salt has more chloride or something like that than Sea Salt... That could be related to your odd result.
(02-26-2015, 11:21 AM)Teck1337 Wrote: [ -> ]Table salt has more chloride or something like that than Sea Salt... That could be related to your odd result.
That's a possibility. As of about an hour ago, the results were the same as earlier. This had to be at more than 90+ hours.
So last night my wife picked up some plain salt (not even iodized) & I just changed the salt & resealed them. I'll check later tonight & then tomorrow afternoon to see if there is any difference.
When I opened the tupperwares earlier, all the readings dropped to around 40% - 45%
I just took a look & after about only 1 hour, the readings are now between 66% - 69%
(02-26-2015, 11:50 PM)Teck1337 Wrote: [ -> ]With Table Salt?
Yeah, Morton's plain salt.
Right now they are all reading 70%-71%
I'll check them again tomorrow afternoon.
I just checked the hygrometers & here are the current readings:
Container #1 70%, 70%, 71%
Container #2 69%, 69%, 70%