Key to the Sawyer, and the Hiker cartridge for that matter, is at least at the end of the season run a dilute bleach solution through it to kill any bacteria, algae, mold, etc., then dry it out for storage.

Sawyer filters are hard to dry completely, so a preseason backflush is in order to clear any clogging (ask me how I know). Luckily, the Hiker cartridge drys quickly and completely.

Cheers,
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--Rick