Heads up on your salt test for Hygrometer

[tazlittleking]

Just purchased a remote oregon scientific hygrometer. Did the salt test and it was really low. It should have been close to 75% and it was at 67%. I got my other digital hygrometer out and put in same bag and they read the same. Talk about pissed and frustrated, the old hygrometer always was tits on. Well after doing some frustrating reading, I have found out it makes a difference on what type of salt you use, and the salt I was using was Potassium Iodide which should be 68.86%.

Here is the percentages that are out there.

SALT BATH PUBLISHED RH AT 25°C
LITHIUM BROMIDE 6.37%
LITHIUM CHLORIDE 11.30%
POTASSIUM ACETATE 22.51%
MAGNESIUM CHLORIDE 32.80%
POTASSIUM CARBONATE 43.16%
MAGNESIUM NITRATE 52.89%
SODIUM BROMIDE 57.57%
POTASSIUM IODIDE 68.86%
SODIUM CHLORIDE 75.30%
POTASSIUM CHLORIDE 84.34%
POTASSIUM SULFATE 97.30%

Obviously most people have sodium chloride, but my wife just recently bought a different brand.
So make sure you check yours. Maybe your hygrometer is closer then you thought.
Mine is 1% off, not 8%! :thumbs:

 

[Ginseng]

Just purchased a remote oregon scientific hygrometer. Did the salt test and it was really low. It should have been close to 75% and it was at 67%. I got my other digital hygrometer out and put in same bag and they read the same. Talk about pissed and frustrated, the old hygrometer always was tits on. Well after doing some frustrating reading, I have found out it makes a difference on what type of salt you use, and the salt I was using was Potassium Iodide which should be 68.86%.

Here is the percentages that are out there.

SALT BATH PUBLISHED RH AT 25°C
LITHIUM BROMIDE 6.37%
LITHIUM CHLORIDE 11.30%
POTASSIUM ACETATE 22.51%
MAGNESIUM CHLORIDE 32.80%
POTASSIUM CARBONATE 43.16%
MAGNESIUM NITRATE 52.89%
SODIUM BROMIDE 57.57%
POTASSIUM IODIDE 68.86%
SODIUM CHLORIDE 75.30%
POTASSIUM CHLORIDE 84.34%
POTASSIUM SULFATE 97.30%

Obviously most people have sodium chloride, but my wife just recently bought a different brand.
So make sure you check yours. Maybe your hygrometer is closer then you thought.
Mine is 1% off, not 8%! :thumbs:

Um,

Good info but you don't just find KI in the grocery store next to the Diamond Crystal or Morton's. Aside from that, you're right that different salts in saturated solution will present different equilibrium relative humidities.

Wilkey

 

[Captain Leafheart]

When it rains, it pours!

 

[tazlittleking]

It actually was purchased at Costco, Leslie brand "Iodized Salt"
Ingredients: Salt, Dextrose, Potassium Iodide, Sodium Bicarbonate, Yellow Prussiate of Soda

Is my wife trying to poison me?

 

[Ginseng]

Ahh,

Good god, what do they put in salt these days?! I buy Kosher salt.

In any case, the salt is probably better than 95% by weight if not more. The small amount of potassium iodide would have little to no effect on the equilibrium humidity.

You'd have to make a salt solution with almost pure KI to get near the listed RH.

Wilkey

 

[NullSmurf]

Ahh,

Good god, what do they put in salt these days?! I buy Kosher salt.

In any case, the salt is probably better than 95% by weight if not more. The small amount of potassium iodide would have little to no effect on the equilibrium humidity.

You'd have to make a salt solution with almost pure KI to get near the listed RH.

Wilkey

Did you use a KI solution to get your hair to do that? :sign:

 

[tomthirtysix]

Ahh,

Good god, what do they put in salt these days?! I buy Kosher salt.

In any case, the salt is probably better than 95% by weight if not more. The small amount of potassium iodide would have little to no effect on the equilibrium humidity.

You'd have to make a salt solution with almost pure KI to get near the listed RH.

Wilkey

Did you use a KI solution to get your hair to do that? :sign:

I think it's JO solution. :laugh:

 

[BlindedByScience]

Professor Ginseng, I see a lot of salt on the shelf at the local food emporium labeled "Iodized Salt". If I'm not mistaken, this is a teeny bit of.....iodine?...added to the salt to keep it from clumping up in the container due to moisture. Hence the whole "When it rains, it pours" slogan that's been around for years.

I always assumed the percentage was teeny compared to the NaCl in the mix. I also assumed that it wouldn't affect the salt test to any degree that I'd care about for calibrating my cigar hygrometer(s). Maybe for analytical chemistry lab work, yes, but not for the cigars. I always assumed that it was way better than +/- 1%

Am I in the ball park here?

Cheers, my friend - B.B.S.

PS: We've taken to buying "sea salt" crystals for use on the dinner table. Comes in a grinder, just like the pepper.

 

[Ginseng]

A quick Googling shows a potassium iodide concentration of 0.006%
That's pretty small but still, it's 60 ppm and iodine is very strong smelling element so I would not be surprised if iodine contributes a smell.

Iodine is added to counter iodine deficiency which can result in thyroid problems. That much I knew from prior readings.

Wilkey

 

[Rob_k]

Ahh,

Good god, what do they put in salt these days?! I buy Kosher salt.

In any case, the salt is probably better than 95% by weight if not more. The small amount of potassium iodide would have little to no effect on the equilibrium humidity.

You'd have to make a salt solution with almost pure KI to get near the listed RH.

Wilkey

Did you use a KI solution to get your hair to do that? :sign:

don't you mean KY? :sign:

 

[tazlittleking]

Just bought Morton Salt which says "This salt does not supply iodide, a necessary nutrient". Did the salt test with it and has held 75% for 10 hours. These are the same hygrometers that read 67% with the iodized salt.

Now I feel confident in my hygrometers. It really does make a difference with the salts and goes along with the chart I had found earlier.

SALT BATH PUBLISHED RH AT 25°C
LITHIUM BROMIDE 6.37%
LITHIUM CHLORIDE 11.30%
POTASSIUM ACETATE 22.51%
MAGNESIUM CHLORIDE 32.80%
POTASSIUM CARBONATE 43.16%
MAGNESIUM NITRATE 52.89%
SODIUM BROMIDE 57.57%
POTASSIUM IODIDE 68.86%
SODIUM CHLORIDE 75.30%
POTASSIUM CHLORIDE 84.34%
POTASSIUM SULFATE 97.30%

I am sure someone out there thinks their hygrometer is way off because of this.

 

[Ginseng]

Just purchased a remote oregon scientific hygrometer. Did the salt test and it was really low. It should have been close to 75% and it was at 67%. I got my other digital hygrometer out and put in same bag and they read the same. Talk about pissed and frustrated, the old hygrometer always was tits on. Well after doing some frustrating reading, I have found out it makes a difference on what type of salt you use, and the salt I was using was Potassium Iodide which should be 68.86%.

Here is the percentages that are out there.

SALT BATH PUBLISHED RH AT 25°C
LITHIUM BROMIDE 6.37%
LITHIUM CHLORIDE 11.30%
POTASSIUM ACETATE 22.51%
MAGNESIUM CHLORIDE 32.80%
POTASSIUM CARBONATE 43.16%
MAGNESIUM NITRATE 52.89%
SODIUM BROMIDE 57.57%
POTASSIUM IODIDE 68.86%
SODIUM CHLORIDE 75.30%
POTASSIUM CHLORIDE 84.34%
POTASSIUM SULFATE 97.30%

Obviously most people have sodium chloride, but my wife just recently bought a different brand.
So make sure you check yours. Maybe your hygrometer is closer then you thought.
Mine is 1% off, not 8%! :thumbs:

I think you still need to clarify exactly what salt it was that your wife bought. Was it an iodized table salt? Was it pure potassium iodide? Forgive me for being skeptical, but there is nothing in the salt test literature that suggests regular table salt (which is typically iodized) is inappropriate for use in the test.

From a chemistry perspective, it is extremely unlikely that 60 parts per million of potassium iodide could drop the equilibrium RH from 75 to 67. Extremely unlikely.

I think there's something else going on that we're missing here.

Wilkey

 

[vortex]

Wilkey is correct. The normal amount added for nutrition to NaCL will have a negligible effect on the data. However, KCl or a mixture of KCl and NaCl is sold as a substitute for NaCL for people with blood pressure problems and this should NOT be used for the test.

And MgSO4 should not be used either but I do recommend taking a bath with it. Wonderful for aches and pains and if you add enough you will float higher in the water, too.

Steve

 

[Ginseng]

Steve,

I've missed you, buddy. That deck at Deer Park is calling...

Wilkey