"fish and dogs can thrive on a bacteria load that could kill a human. the bacteria population could be WAY imbalanced toward the unhealthy for humans side of the scales. now, it true your body could detox those bacteria, but why provide more of a toxic load on your body than is necessary?"
Yep, yep... BUT the reason they can handle the load is they are closer to their eden than we are to ours.
IF (that is a big if) I had full control over a small, self sustaining natural (excepting the air, rain and maybe clean area run off) body of water I would probably start out slow and TEACH my body to live with what it was designed to live with; NOT to live against it.