Yes, it can happen, I have no disagreement there, but this usually takes place when one is underfiltered (lack of bio filtration volume), or has a tank where the bio bacteria is not well established. Or as Big_One suggested, the person performing the water change was an idjit, & added straight untreated tap water where the chlorine/chloramine killed the bio bacteria.
As I stated originally, in an established tank, with established bio filters, 90% water changes will not cause ones tank to cycle.
I've swapped out established filters, placed them on a new set up, with 100% fresh tap water (treated with proper water treatment of course) and never had a hint of a cycle. Been there, done that, more times than I can count.
As I stated originally, in an established tank, with established bio filters, 90% water changes will not cause ones tank to cycle.
I've swapped out established filters, placed them on a new set up, with 100% fresh tap water (treated with proper water treatment of course) and never had a hint of a cycle. Been there, done that, more times than I can count.
