the foam humidifier is supposed to be charged with 50/50 solution, not plain distilled water. Truthfully, dont bother using the foam humidifer. in airtight travel humidors, even humidifiers filled with the 50/50 solution tend too overhumidify. there are several good alternatives to the foam humidifer. first, a Boveda will work great. its cheap, and should last at least a year in an airtight travel humidor. another choice is my humidity sheets that are mentioned in the post above yours. another choice would be too take apart your humidifier, throw out the green foam, and replace with Heartfelt beads. another choice is the "puck" from Cigarmony. bottom line is dont use the humidifer that comes with your travel humi. it could damage your cigars.