Nitrosomanas and nitrobacter live in your res and soil, yes. They are the two species of bacteria responsible for the nitrogen cycle i.e. ammonia-nitrite-nitrate. They are beneficial obviously for that reason, also for outcompeting unwanted microbes. I use products to INCREASE biological activity in my res, it is an active eco system itself and I find that when in ballance, this is the best way to keep it. Of course with peroxide or similar, there are definite benefits as far as keeping unwanted organisms at bay but for me I prefer to aim for a ballanced ecosystem. Not all nutes need microbial activity to be usefull, depends on their structure... trick ass bitches