Originally Posted by _Sam
So even though we have done a complete water change, cleaned the gravel, etc. We should still expect the ammoina level to be high, without fish, untill it's been through a full cycle?
Yes, cleaning doesn't matter, all new tanks will go through the cycling process UNLESS, you take everything from the other tank, filters /gravel /decor and put them in the new tank, you cannot let anything dry out in this process though, but to be on the safe side I would just seed the other tank and let it cycle keeping fish in the already cycled tank then transfer fish, shouldn't take more than 3 weeks.
Water doesn't hold nitrifying bacteria which is the bacteria in your filter/ gravel/ Decor that eat ammonia and nitrite and turn them into nitrate.