My Heartfelt beads cannot maintain a proper RH no matter what I try. Help / Advise please??

About two months ago I purchased a half pound of 65% Heartfelt beads for my two identical, Balley II Glass top humidors (http://goo.gl/R0K1G). The humidors are 865 cubic inches. According to Heartfelts math (http://www.heartfeltindustries.com/Bead_Set_Up.asp) I need 1.6oz of beads per humidor. I split up the beads into four 2oz nylon bags, gave them the prescribed 3.5 teaspoons of distilled water with a syringe. Placed two 2oz bags in each humidor. With the extra beads, the recovery time from opening the lid should be very fast and should also make up for any leaking that might occur from the glass top, though thats never been an issue in the past. They stayed nice and steady at 64% for about a month and then it slowly started to dip. About 62% I added more distilled water but nothing happened. It continued its slowly, steady slide until it reached 60%. At that point I ordered more beads. This time I got the 70%. Broke them up and prepared them the same way I did with the 65% beads. After 24 hours with BOTH the 65% beads and 70% beads (8oz of beads per humi) both humidors are sitting at 62%. Here is a picture of their placement within the humidor http://i.imgur.com/tmNDQ.jpg . Black bags are 65% beads, brown is 70% beads. Anyone? Bueller? Help??

Some side notes;

• For the last 2 years I have no had ANY problems with maintaining a rh between 65% and 70% with bovida packs or PG solution.

• The humidors are not located anywhere near an AC/Heater vent or return.

• Because trhey are glass top Im not compulsively opening and closing the lid. Stays closed days on end.

• The hydrometer is perfectly calibrated as of 2 weeks ago with a bovida calibration pack (Salt method)

• Its rainy today here in Philly and the ambient humidity outside is 87%, 62% in the humidors http://i.imgur.com/wwXw4.jpg

TL/DR My heartfelt beads are working for shit I dont know why. Help?