Of course, we don’t know. And these tests only show the bacterial load, nothing about the species, some of which are indeed helpful in the maintenance of water quality. Nevertheless, I’m curious to see the results.
@RafEg That recipe probably includes something like agar and some sort of nutrient, usually bovine serum albumin (BSA), but any beef broth will do. I guess all biology students had to do that at one time during their studies. Even me, and I’m not a ‘wet-lab’ biologist. Try searching the internet for ‘home-made petri dish’ or something like that.