Theory on bacterial blooms in new tanks

I once read something that was promoting the use of non-pasteurized milk and it said that when non-pasteurized milk goes bad its a zoo of bacterial species reproducing while when pasteurized milk goes bad its a monoculture of baccillus bacteria because the baccillus spore survives pasteurization. The article claimed that this somehow meant old non pasteurized milk wasn't as bad to drink as we think it is. Well, this argument failed to convince me to drink non- pasteurized milk but it did stay in my head.

I recently set up a new 20g tank from the petco sale and as often happens the water turned white from a bacterial bloom. I started thinking and wondered if maybe the bloom was a baccillus monoculture since these bacteria produce spores which are on every single thing we touch, only a minority of bacteria produce spores. So over two days I put around 5 gallons of water from my established 10g tank into the the new 20g to try and create a diverse bacterial culture in the new tank.

The cloudiness of the water has gone down since I did this but not dramatically enough to prove anything. I figure by tomorrow the water should be looking normal. I can't tell if adding water from the established tank helped but it didn't hurt and might be worth a try.