Nitrite is deadly, so any amount showing on tests above zero requires a major water change.
You have another fish store whose advice is shaky at best. I am telling you that floating plants would be your best course of action here, as they gobble up ammonia, and do not produce nitrite, saving the fish.
You have another fish store whose advice is shaky at best. I am telling you that floating plants would be your best course of action here, as they gobble up ammonia, and do not produce nitrite, saving the fish.