If you use the search function, you will find extensive documentation that I have done experimenting with the relative humidity of powder inside sealed containers, using a variety of devices and observational and quasi experimental methods.
At one point, I had multiple humidity packs in each container, dozens of them in action at any given time. Got on the bandwagon before I understood enough about powder humidity
I have removed them all and I don’t utilize them anymore
The only full proof way to keep powder humidity constant at around 50%, which is where you want it, is to keep it in a cool place 70° or below with a relatively constant humidity near 50%
If you do your reloading somewhere else, take the powder from this temperature and humidity controlled environment, only long enough to do your reloading session and then replace it to that controlled environment
It is the only way
If you put those humidity packs in there, and then move that canister around to different temperatures, moisture exchanges with that humidity pack and changes the total water content of your powder, which is what you are interested in - not the RH per se
The total water content of your powder can stay exactly the same, but the relative humidity change as the temperature goes up and down. Conversely, if you put that RH pack in there in garage in winter, it will remove moisture from the powder. Then, as it heats up in the summer, it will add the imposture back to the powder. Fluctuation water content in the powder is exactly what we DONT want
So we are back to square one: put your powder in the basement at about 60° and 50% relative humidity and leave it there. It is the only way
For those of you who are using the relative humidity packs, in addition to the above, I suggest that you
- Tell me how you know how many of those humidity packs that are intended for a cigar box are necessary to equilibrate the humidity inside an 8 pound canister filled with a certain and probably fluctuating proportion of powder and air
-go read about guys who use them for cigars; those are not closed systems
- Tell me how long it takes the powder to equilibrate, even if you do have an optimal number of packs inside
-tell me whether or not during this equilibration, the humidity pack that is on top of the powder column is causing a gradient of humidity along the depth of the power. If it is, how long does it take for equilibrium to be established and abolish that gradient?