Excellent info! Apparently I didn't drill deep enough into the website.

This statement from the Globalhydration .pdf is particularly useful to me: "Cattle faeces appear to be the primary source of Cryptosporidium, although these parasites have also been
found in humans and other animals." This gives me a good indication of areas where Aquatabs will probably be sufficient, and areas where additional/other methods should be used.

EDIT: The two-part chlorine dioxide products seem to claim full effectiveness against Cryptosporidium. If anyone has information to the contrary, I would appreciate the details. Or thoughts on other drawbacks (aside from inconvenience and leaky vials).