The Sport Berkey® Portable Water Filter has a shelf life of 50 years. When the filter system will not be used for an extended period, remove filter and fill the unit with either chlorinated bleach of 1/4 tsp. per one half gallon of water, or a 50/50 mix of 3% Hydrogen Peroxide. Rinse. Allow parts to dry thoroughly with cap removed. Re-assemble and seal in an air tight container if possible. Do not allow filter to freeze, do not place in microwave oven and do not run hot water through the filter.
We recommend that the bleach used, not be scented or in any other way enhanced. If you are not aware, many bleaches today come with “other things” in them to provide a nice smell, etc. We don’t recommend these types of bleaches.