If you're planning to cycle this new tank so you can put fish in it, then putting old water into the new tank isn't going to do much. There's little or no good bacteria in the old water. It lives on all the surfaces in the old tank. Put some gravel, plants, decorations from the old tank or the best thing is put some of the old filter material into the new tank's filter.
"Fear not, my young apprentice. Just change the tank water."