we who are opinionated in cycling threads list only three conditions that could impact bacteria to the point we'd consider it a cycling offense: 1. extreme temps no home aquarium will ever see 2. true drying out. not emersion of live rock for eight minutes, but true systemic drying 3. medication events of direct antimicrobial effect, rare.
people who are treating fish already know its antimicrobial that doesn't count, im talking surprise or unaccounted for actions.
whats not on the list, bacteria withstand:
skimming
withholding feed (you cant starve a system into sterility, microbiologists only wish)
minor variances in salinity
something a kid dumped in the water
you can drain a system for a long time and not kill filter bacteria protectively housed in scum