As Rebbecca mentioned, days won't do. Make it for at least one month.
Make sure that if you use the fridge, you provide indirect moisture to the ooth. The fridge literally sucks out all moisture, leaving the air quite dry, which will dessicate your ooth. When using the fridge, I usually place my ooths in a zip-lock bag. I also add a small paper towel to surround the ooth. Finally, I make sure that a corner of the towel is wet. You don't want the moisture to come in direct contact with the ooth in order to prevent mold/fungal growth, but the moisture will dissociate and distribute in the bag, providing some humidity. Every week I add a couple drops of water to the corner of the paper towel as it too tends to dry out a bit. For the past three seasons I have used this method without any problems at all... Of course I did it with another species, though.
This winter I am utilizing my unheated garage to provide a cold period for all my ooths. The temperatures outside fluctuate from the night's low to the daytime high and the ooths receive a more natural cold period. Of course, I spray The paper towel substrate in each container to maintain some humidity.