if you refridgerate your opened bottle of cgd it should last for several months with no problem. i go through about one of the big 2.5lb tubs every month and that lasts fine in my warm herp room.

i used to mix up bigger batches and freeze it in little mini ice cube trays i found at target too. that worked pretty well except that the mini cubes were hard to get out without a little hot water on the back of the tray to loosen them.