ChemiPure usually lasts 4-6 months. You could save a bunch of money just buying bulk gfo and carbon and a couple filter sock bags or just using the bag your ChemiPure is in now, and change that out monthly. You would need like 1/2 tbspn gfo and like 1 1/2 tbspn carbon for that little edge you have. Even small containers would last you a very long time.