I’ve used a lot of different things to clean the water that I drink in the backcountry. I have bought fancy filters and Ultra Violet light pens. Out of all the different ways to keep myself from getting sick in the backcountry the best I think is the cheapest, simplest, and lightest. I use regular Clorox bleach. A gallon goes for about $4.00 at most major retailers; you can find the empty eye drop bottles for sale on the internet for right around $1.00 with shipping. The problem with buying the bleach is it will lose its potency after about a year so if you have old bleach from last season you might want to throw it out. I use two drops per liter (or quart) and wait twenty minutes before I drink it or add anything to the water. This is very important if you add a sugar drink mix i.e. Gatorade or PowerAde the sugar can cause a chemical reaction that will make the water treatment ineffective. Also, if you are averse to paying for a whole gallon of bleach take your eye dropper to a restaurant with you and ask your waiter or waitress if they would fill it up in the back for you and then give them a good tip. A one ounce bottle lasts me through the summer without needing to refill it, also the statistics on how effective this treatment is you can find out more at https://www.epa.gov/ground-water-and-drinking-water/emergency-disinfection-drinking-water. Anecdotally I have been using bleach to treat my water in the backcountry since 2013 and I have never gotten sick also I have never had it brake, malfunction, or need to clean it. However, it does taste a little like pool water.