Thanks pika! I never though about drop size. The bottle I use isn't from BPL, It's just a bottle I salvagaged from some regular eyedrops. To determine my drop size, I had to do a little experiment since I don't have a measuring teaspoon. I figure bleach has to be pretty darn close to water in weight, so I used my digital scale to determine how many drops I should be using. It's not an exact science by any means, but I used the ratio of 1g = 1mL of bleach. After 35 drops, I reached 1 gram. I double checked it by adding 35 more drops, and sure enough, I reach 2 grams. So, if he recommends using about 0.2mL for every liter of water, I should be adding about 7 drops. It seems like my drop size may be a bit on the small side, but it wasn't too far off. I have used more than 5 drops a liter before, but now I'll know that I can add more if I think it's necessary. I use a 2-liter bottle, so I'll keep the range between 10 and 20 drops. As far as effectiveness goes, you're right. It is at least a step up from iodine, right? Even though they're supposed to be more effective, I have yet to try any chlorine dioxide tablets. The only real reason I've avoided them is because I figured they go bad just like Aquamira does - is this true? Also, does anyone know if there is any real difference between Micropur and Potable Aqua?

Thanks,
Eric