they will take days even weeks to remove any substantial amount of moisture. This might be little known but taulman has had this for years. http://taulman3d.com/drying-materials.html

those moisture packs only work to absorb moisture that enters the containers or bags it doesn't remove any from it unless your heating the filament.
I use a toaster oven turned re-flow oven programmed with a 24hour dry cycle that holds the temperature at 50*C to get the job done for a few rolls at a time