HAVE TO WAIT A BIT FOR THEM TO WORK – The results aren’t immediate with Micropur tabs. You’ll have to wait up to four hours for clean water depending on the situation and what you’re wanting to remove. Cryptosporidium will take the full four hour incubation time before it’s completely removed, but crypto isn’t very common in most backcountry water you’ll encounter.
Unless we’re in an area where water has been tainted by livestock feces, we typically only wait about 15 minutes before considering our water safe to drink since that’s the contact time required to eliminate the most common harmful stuff. We’ve never had any issues, but we recommend you use your own best judgment to decide how long you want to wait as it’s a matter of health. Colder water requires more time, and of course if you want to be 100% certain that your water is completely pure – you should wait the full four hours.