Fascinating.
While I've never had biogrowth problems in my water tanks, I'm lucky enough to be on a good public water supply. But occasionally I travel further.
I don't get involved in sterilization, but I do have
cooling towers to treat. So I find all of the ideas interesting. Of course, we have to watch scale and
corrosion at the same time, so thing are not so simple. We don't worry about spores, only biomass. Reinfection is continuous (airborne).
Regarding blanket statements about what kills what, they can be silly. Sufficiently dilute, none of these will
work. Sufficiently strong, all of these will kill everything and dissolve it too. Where is the middle ground?
The USEPA has this to say about anthrax spores:
Anthrax Spore Decontamination using Bleach (Sodium Hypochlorite) | Pesticides | US EPA
Basically 25% household bleach in water with enough vinegar to take the pH to 7; this is strong stuff. Contact time is 60 minutes. Certainly a way to clean a tank, if all surfaces are in reach. I really don't believe anything can be sterilized unless all of the physical dirt is removed; bugs can hide from most anything under
corrosion or biomass.
Interestingly, bleach is generally more effective as a chemical oxidizing agent at high pH (10+). Interesting to ponder; the requirements of a cleaner and disinfectant are different, hinting why most bleach cleaners cannot excel at both. They are cleaners.
Statements regarding whether a tank will remain sterile for weeks or months seem beside the point; the tank will be refilled in days. What matters is practical on-going treatment.
Vinegar. Enough to sterilize water will render the water unusable for any purpose. I run waste plants that biodegrade dilute organic acids using bacteria. They love it. I dislike vinegar anyway.
Bleach. Hard or impossible to use enough without the water getting nasty.
Chloramine. Rather like bleach, without getting into the details. Lasts longer. I generally like this approach, but it does take more care. Not effective on everything.
H2O2. Sure. Problems discussed in other posts.
-----
Honestly, if I wanted safe
drinking water in the 3rd world I would use a spore-specific filtration system for the
drinking water only. The rest I would slightly over treat with bleach and not worry if it was imperfect.
And I like both
beer and tea. Proven safe.