So what can potential fish- in cyclers due to avoid risking fish with the dreaded: dead bottle of bottle bac? If they input fish with dead bac, and no testing, the fish will die.
input your water and rocks sand and bottle bac, use liquid ammonium chloride to see if oxidation is present/ live bottle bac. Then it’s safe like the directions say.
your sample does not have to boost to 2 ppm, it needs to be one ammonia test ran on the clean water so you get a baseline zero for the particular non digital kit being used, keep that first picture handy.
second step is add tiny amounts of liquid AC until the tester shows one degree up from calibrated zero, a tiny increment up on the second test picture showing slight ammonia +, take second picture of the boosted ammonia test.
in 24 hours take a third picture of the aquarium water sample read after it sits overnite with bottle bac in place, if it’s like pic #1 your bac are alive, go. Choose your disease protocol wisely: ‘go’ is different for many people we can see. Go simply means your tank will handle the bioload you choose to start with, like reef conventions where 500 reefs all cycle by a Friday without variation for twenty years and thousands of reefs, like ten thousand fish-in cycles we can see are running just fine. To use non digital ammonia tests better, don’t look or wait for hard zero, look for calibrated movement down.
if anyone is thinking dead bottle bac are common, post a link of a fish-in cycle that didn’t work.
if we put clownfish into a new ten gallon tank with water, dry sand dry rocks no bottle bac, does anyone here think they’ll live past three days?
ergo
fish in cycle + 3 days duration acting normal, fish were never burnt and bottle bac confirmed alive. In hindsight we can see fish in cycling hasn’t been harming fish, they’re safer though using the pre testing (But aren’t gonna do it

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Dr Reefs bottle 90 page bac work thread shows most all brands of bottle bac adhere to surfaces within a few days max, and a full water change still passed oxidation testing revealing true surface inoculation in place, this is the updated definition of a completed cycle. its never about nitrite in updated cycle science, we only care about free ammonia. Whatever nitrite reads at any stage of reefing: doesn’t matter. We’ve just about distilled why forum cycles stall, always, but MACNA convention reefs never do.