A. Among all the foams, the green floral foam is the worst. Since it is hard, it occupies over 80% of the volume of the container - you'd have to drip your solution in over an hour's time to get it to absorb all the way into the middle.
Crystals vs. Foam: Crystals absorb over 400x their volume (size) of the solution. Thus, you can put much more volume of solution in your device than you can with foam, which occupies a much larger volume of the container.
PG Solution vs. Distilled Water: I cannot recommend ever using distilled water - you will get spikes and valleys in the relative humidity inside your humidor, and unless you watch it closely, this can cause cracking of your cigar wrappers.
In sum, the crystals are the best way to go to reduce your "fillup trips" to the humidor. PG solution is the way to go for constant humidity. Now, XIKAR PG solution is not 50/50. The reason is that the Propylene Glycol breaks down slower than the absorption rate of the distilled water. So, if you continue to add 50/50, eventually you have all PG and no water to humidify your container. Thus, people use distilled water on top of 50/50 so that they don't have this effect. But, how do you know when the PG is gone and you will start getting spikes?
Answer courtesy of Kurt Van Keppel, President of XIKAR, Inc.
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