Boveda hygro calibration being weird?

asolomon

I just picked up a Boveda hygrometer calibration pack to finally calibrate my hygrometer (digital, Springfield, one of those Walmart ones). It's got a small ziplock with a 75.5% humidification packet inside. It's a little big so that in order to fit it into the ziplock it has to overlap a bit with the humidification packet and the bag scrunches up. Doing this, the hygro reads a consistent 70%, right away and stays for over a day. Then I took the hygro and the humidifier out of the Boveda ziplock and put them in a larger ziplock from my house, next to each other but not touching. Right away, the hygro went up to 74%, but then after a few minutes started to climb down all the way to 65%, and stayed around there for the day. So I have no idea how to read this. My hygro is giving me some pretty wacky readings from this calibration pack. It reads 70% in the included ziplock but that's too small so I think that might not be accurate. My theory is that it's accurate within about 1% (that's why it said 74% in the larger ziplock) but the small humidification packet is too weak to humidify the larger ziplock, so that's why the reading started to go down. Any thoughts?

The Sniper

Your logic seems solid to me. Do you have any other hygro's, or is this your first? If you do, there's a couple of things you can try... put the new hygro next to another you own (which I assume you calibrated previously), or try putting your old hygro in the calibration pack & see what it says.

Worse comes to worse, you can always do a salt test (do a search of the forums and I bet it comes back with at least one "how to" result) and see what that gives you on the new hygro.

Hope this helps, good luck!

MrMoke

I have one of those boveda packs, unused myself. It arrived after I did the "salt test" with my existing hygros with satisfactory results. I'd go with what the Sniper suggests. I have a hunch that the Boveda pack simply contains a saline solution and does the same thing as the salt test anyhow.

The Cank

The Sniper:

Your logic seems solid to me. Do you have any other hygro's, or is this your first? If you do, there's a couple of things you can try... put the new hygro next to another you own (which I assume you calibrated previously), or try putting your old hygro in the calibration pack & see what it says.

Worse comes to worse, you can always do a salt test (do a search of the forums and I bet it comes back with at least one "how to" result) and see what that gives you on the new hygro.

Hope this helps, good luck!

NNOOOOOO not the salt test ! it is unreliable. I always use the Boveda calibration kits. I have never had a salt test be accurate. Man I would almost say get a smaller hygro or get two packs and throw them in a big zip loce. I just wouldnt trust the salt test. I know many do but I dont

The Sniper

The Cank:

The Sniper:

Your logic seems solid to me. Do you have any other hygro's, or is this your first? If you do, there's a couple of things you can try... put the new hygro next to another you own (which I assume you calibrated previously), or try putting your old hygro in the calibration pack & see what it says.

Worse comes to worse, you can always do a salt test (do a search of the forums and I bet it comes back with at least one "how to" result) and see what that gives you on the new hygro.

Hope this helps, good luck!

NNOOOOOO not the salt test ! it is unreliable. I always use the Boveda calibration kits. I have never had a salt test be accurate. Man I would almost say get a smaller hygro or get two packs and throw them in a big zip loce. I just wouldnt trust the salt test. I know many do but I dont

Hence the "Worse comes to worse..." in my post above - Cank has the right of it, in that the salt test has more probability of human error. A known commodity to test an unknown against is always the best choice!

kuzi16

The Sniper:

The Cank:

The Sniper:

Your logic seems solid to me. Do you have any other hygro's, or is this your first? If you do, there's a couple of things you can try... put the new hygro next to another you own (which I assume you calibrated previously), or try putting your old hygro in the calibration pack & see what it says.

Worse comes to worse, you can always do a salt test (do a search of the forums and I bet it comes back with at least one "how to" result) and see what that gives you on the new hygro.

Hope this helps, good luck!

NNOOOOOO not the salt test ! it is unreliable. I always use the Boveda calibration kits. I have never had a salt test be accurate. Man I would almost say get a smaller hygro or get two packs and throw them in a big zip loce. I just wouldnt trust the salt test. I know many do but I dont

Hence the "Worse comes to worse..." in my post above - Cank has the right of it, in that the salt test has more probability of human error. A known commodity to test an unknown against is always the best choice!

every time i have used the salt test my hygrometer giver the same readout.


someone asked me about the salt to water ratio once. if you want to remove some of the human element then use this ratio:

3 parts salt and 1 part water.

i usually go with 1 level TBS salt then 1 tsp water.

this should yield a good "salt paste" that will give an accurate reading. i try and leave in a dark area for about 36 hours. all this in a quart sized zip-loc. i dont try to remove or add air. whatever is in there, is in there.
i retest every year or every time i replace a battery.

aron325

i used the boveda hygro cal kit and ended up perfect i didnt have a problem with the bag being too small either. i dont know maybe your hygro is too big lol. i would retest with a slightly bigger bag and see what you get. from there salt test it.

MrMoke

I've found the salt test to be at least consistent therefore probably reliable, calibrated 3 hygros in a row one after the other then placed them all in the same humi, they read the same, so over the 4 days and 3 bag openings the hygros got set to the same, here's where the assumption comes in, at 75%, if there was a margin of error I would expect it to be variable, things don't usually go wrong the same way multiple times!!

Russ55

I'd also suggest getting a smaller Hygro. If not for the calibration kit then for the real estate a Hygrometer that size is going to take up.

As far as the salt test is concerned...there's too much room for human error for my liking, but other people do use it regularly, and successfully. Following Kuzi's instructions up there is probably your best bet if you want to try it out.