Hey, I am having the exact same problem. I just bought one of those tubes. It did not help what so ever. I have a tupperware dish of distilled water, and as soon as I take it out it goes from a perfect 70% down to 50%. I just can not figure it out. I have recalibrated my hydrometer two times . In addition to that I have checked the seal and that is also o.k. Would buying another humidifer maybe work work? I only have a small 25 cigar desk top one with a small hockeypuck size humidor. Any suggestions?