The sand did not lose bacteria. We do not have to feed established bacteria (on sand grains in a big bag of water vs pure culture bottle bac strains in suspension with an expiry date) merely keep them wet, as they're still being fed even if we don't see how and in some settings their dormancy ability is measured in multiple year increments. Now if it sat there twenty years I'd be interested to see an incubated inoc plate ran from a test, but 1-3 yrs not even a concern. Twenty may not be long enough, truly it could take longer to self sterilize.
Pre rinse all these sands before use, rinsing doesn't sterilize grains either, merely removes silicate sand and initial clouding. Tip of the century. The type of sands one wouldn't pre rinse are sands with crabs, snails, worms, crustaceans all within.
No bagged sand from lfs has those, so rinse before use bigtime. I use tap water that way I can prep it to cloudless perfection and opt out of early diatom phases right away, by not starting with a powdery component which helps nothing. Once set in filtration bacteria are set, it takes a medication event to undo things. Heres three year old ocean direct sand passing a rip clean test (disturb/no cloud/never an invasion of any type) right before I put corals and rock back in
Start live sand this clean unless you are truly buying animals mixed within
Start that clean, then -buy- animals to put in from refugium pack sellers is ideal.
