GrumpyGord:

Micropur tablets and AM liquids use identical active ingredients: chlorine dioxide. If you read the ingredients, you will note that Micropur has 3 times the concentration of chlorine dioxide. So:

1. Micropur is EPA registered and is allowed to advertise effectiveness against all three classes of baddies: viruses, bacteria, and protozoa (crypto, giardia, etc.). Treatment times are 15 minutes for the first two -- and 30 minutes to 4HOURS for the third -- depending on water temp (the colder, the longer).

2. A.M. being a weaker solution cannot obtain EPA registration and is NOT allowed to mention either viruses or protozoa! If you read the AM packaging, you will note that ONLY bacteria is mentioned -- along with the shorter treatment time.

3. When I talked to an A.M. rep -- she said I could replicate Micropur's efficacy against protozoa by simply quadrupling the dosage. Mathematically, it should be tripling, but she said quadrupling. Be it 3 or 4 times, that makes AM both slower to use (counting drops, 5-min mixing period, etc.) -- and more expensive!

4. Finally, just last year, A.M. came out with its own tablets! Interestingly, if you ignore the A.M. labeling and just compare the packaging and ingredient percentages -- they are identical to Micropur! And both are made in Spain. I am willing to bet it's the same factory making the tablets for both brands!