just a couple thoughts and Ideas regarding Bio BBs and their storage.
there are some thoughts running around that Bios will break down and fall apart with in a few days of opening the bag, well not true. though shelf life is a concern you have longer than you might think, but to be safe and keep those BBs solid, here is a couple tips that may help.
Keep them in a box some place out of sun light, keep them cool and dry, keep the bag closed, use a freezer zip lock and put in a silica gel bag, this way they will last months.
you can find these silica gel bags everywhere, pill bottles, electronic packaging etc. - and some dry foods from Asia
http://en.wikipedia.org/wiki/Silica_gel