librarygirl
Look It Up
Well whatever harm to the cycle that washing/changing the media did it's already done, the bacteria just need to reform. I'd do the water changes on the new tank as Jlk suggested and move as much media and stuff over from the 50 to the new tank with the fish, then move as much stuff from the coldwater tank to the 50 with the fish. Test each tank daily and do water changes as needed until ammonia and/or nitrite go back to 0 if either of these start to rise.