Raising the humidity in my cooler/cave with saturated NaCl

[Scarlet Runner]

After reading many posts on this board suggesting that maintaining ~80% humidity in a cave is harder than it looks, I began to suspect that my little humidity meter (a freebie in years past from orchid growing supplies) was substantially off.  It has been telling me that I'm sitting pretty (in my cooler with 2 pie pans of water at 55F) at about 75-80% humidity. 

I bought a new digital humidity gauge and confirmed its accuracy using the salt +DI water slurry method, and then threw it into the cave, to find that I'm actually at around 50% humidity.  So, since the salt + DI slurry brings the air to 75% humidity (the basis of the accuracy test), I figured I'd try that in the cooler.  I added a small bowl of salt slurry, and today the humidity is up to 80%, according to the new digital gauge.

Has anyone else tried this? I still disbelieve for some reason....

[Scarlet Runner]

Update: The new digital humidity gauge has been reading 99% humidity steadily for a while now.  My little cheapy analog (?) gauge also reads high- above 75%.  I still have a hard time believing that a little bowl of saturated salt/water (and two pie tins of water) sitting in a cooler at 52F could raise the humidity that high.  It doesn't feel very humid when I open it... any ideas?

[Trisha in WA]

I know this is an old thread, but I would be really interested in hearing if you still think the salt water is helping. I am needing to up the humidity in my little cave as well.
Trisha

[Tomer1]

Above 80-85% theres a large error with the cheaper digital meters.

[Scarlet Runner]

Update for those curious: Humidity (digital gauge) had read steady at about ~75% humidity through this Spring and so far this Summer.  the temp in my cooler/cave has climbed up to about 65 F.  We've had more than average rainfall this year, so I don't know how much dampness in the crawl-space (where I store my cooler, closed, but unlatched) contributes.  I haven't taken the salt slurry out and tried plain water, but it seems to me that maintaining ~75% humidity is pretty good. And, as Tomer notes, I think these are all "ballpark" measurements anyway.

Trisha- try it and see?  Very easy to mix up a few TB of salt + water in a cup and throw it in there and see what happens...

[Tea]

To get a quick humidity rise in my fridge while trying to get my brie's to bloom, I resorted to putting a container of hot water in there for 4-5 days.  Haven't tried long term though, so the salt water is worth a try.