If it helps, water is not something that can be considered "cycled", and using water from a mature tank will not help a brand new tank cycle faster
The nitrifying bacteria that process ammonia largely populate surfaces such as rocks, sand, bio media, glass, etc. Very few are free floating in the water column.
That said, using water from a mature display tank added to a QT tank can do a lot to keep water parameters similar across both tanks, which is what that poster you quoted is doing. But, using water alone cannot quickly cycle a brand new tank, as far as the initial nitrogen cycle is concerned
I hope that helps!