Need help deciding between water purification tablets, and a water filtration pump
Water is full of bacteria, protozoa, viruses, dirt, and harmful chemicals. You can bring purification tablets, or you can bring a filter pump. Either way, it’s best to strain water from the clearest part of the stream.
Water Purification Tablets
Water purification tablets, usually iodine, will kill most living things in the water. They will kill bacteria and protozoa, but they will not kill viruses or endospores. Certain microbial organisms will go dormant and form a protective shell to survive unfavorable conditions, called an endospore. Some endospores are extremely durable, and can survive iodine purification, or even boiling (such as botulism). Giardia and Cryptosporidium form endospores, so purification tablets might not stop them. Iodine tablets can leave an unpleasant taste behind. After waiting the 30 minutes for the iodine to work, you may want to add a drink flavor mix to provide a more pleasant taste. You can also add a vitamin C or ascorbic acid tablet to neutralize the iodine. It will neutralize the flavor of the iodine, but if you add the flavor neutralizer pill before waiting the full 30 minutes, it will form a precipitate with the iodine, deactivating it before it has a chance to purify. Tablets are cheap and light, and so they are nice for short trips or emergency survival situations. Iodine tablets will last almost indefinitely if they are sealed. If they are exposed to the air, then they will start to lose their effectiveness after a few days as they sublimate (solid iodine is converted to a gas and diffuses away). Tablets also won’t remove any sediment or sticks that are in your water.
PROS: light, cheap, easy
CONS: limited use, don’t kill everything, require 30 minutes to work, unpleasant taste, limited quantity
Water Filtration Pump
Pumps force water through a filter with very small holes. Most pumps will filter down to 2 micrometers, which will remove everything but the small viruses. Filtration pumps are more expensive, but can produce much cleaner water. Pumps will last a long time, but the filter will need to be replaced after a few years as it gets more clogged with ultra fine sediment, and it becomes difficult to pump water through. Pumps can generate drinking water quickly, but require effort to pump them. They take up more space than the tablets, but can provide more reliable cleansing. You may want to take a few tablets as back up for the pump, in case the filter gets clogged or broken. You can pump dirty water through the filter, and it will clean out sediment, but it will clog the filter faster, so it is better to collect water from the deepest, clearest part of the stream, and strain it through a sock or shirt to keep any twigs out.
PROS: clean, efficient, better taste, large volumes of water, faster, filter cartridges last a long time
CONS: filter cartridges can get clogged, more expensive, don’t filter out smaller viruses, heavier and bulkier