I use this theory in my fishroom too and it has worked fine for me, I usually only clean filters when I notice they aren't flowing much and ran 40 tanks in my old fishroom (current one is still getting setup) on this principle for over a year with no issues. What works for me may not work for others, and sometimes what is recommended (based on theory) doesn't actually work in real life. I find things with these "bacteria" very hard to believe and wonder how much scientific backing every theory has.