Re: Water purifier
Katadyn Pocket is expensive but well built. The filters last forever and it is reasonable to pump for multiple people. It is field serviceable as well. It is probably way too heavy to carry for just one person on shorter trips though.
The Katadyn Mini filter is much cheaper, lighter but has a low flow. For one person it's OK. Two or more it will be a lot of work. This is the filter I take when I want something lightweight and small for solo camping or day hikes where I think I'll need to refill my water.
The Katadyn water bottles also are a good option because they are really easy to operate.
The paper filter pump models I avoid after I had one clog up really bad on a trip when some sediment was accidentally sucked into it. The paper filters, once clogged, are essentially not field serviceable. They can be scrubbed on a little, but you risk tearing a hole in it. The ceramic Katadyn and other models are all field cleanable but you do need to be careful that you don't drop the filter. I also have heard that you not let them freeze when full of water which can crack them.
MSR has some ceramic filters as well, but I've not tried them yet. Many people like them however.
If you are going into an area where virus contamination is an issue then you should look for a filter with an iodine module as well. Ceramic and paper filters cannot filter out viruses. If you are in the US or north this will probably not be an issue.
Polar Pure (
http://www.polarequipment.com) is iodine and works well for shorter trips and emergencies. It will leave an after taste in the water, but the small size makes it a good addition to an emergency kit and it won't expire (it's just crystal iodine). You can mix in something like Tang and it will knock out the iodine aftertaste. I'm not sure if using iodine like this is a good long term solution though but this will supposedly kill viruses in water.
I'd avoid the UV filters or anything with batteries. A friend with the UV filter light did get Giardia. The doctor speculates that the water he drank had sediment in it with pores that shielded the protozoa from the UV exposure and didn't kill everything.
