Way to sanitize hot ponds/check bacterial levels?

[Lodestone]

Bacteria in the pools is almost entirely not cased by man. Bacteria is basically EVERYWHERE in nature (except for extreme freezing conditions), and nearly everywhere else as well. Some bacteria is harmful, most has no effect on us, and some is actually beneficial.
In short:
moist = bacteria
standing water = more bacteria
warm standing water = even more bacteria
warm standing water with gobs of decaying leaves and mud = lots and lots of bacteria.