Cycling 2nd Tank.

If I were you, I'd transfer some of the media from your fully cycled tank into the filter of the main tank.
Just a few ceramic noodles or bio balls should speed up the process dramatically.

Alternatively, if you have a sponge filter in your other tank, take it and squeeze it into the new tank, this will also transfer some bacteria to start the process.

Because bacteria grows on all surfaces, including those on the artificial plants, putting those in the new tank will also help.

Doing those things Extreme suggests will make the cycle go faster, both fishless and fish-in. You didn't say, but if it will be a fishless cycle things will behave differently from one with no mature media, plants etc. If you look at Jesnon's thread you'll get an idea. She moved house to another town, gave her fish away but kept the media wet then recycled it several weeks later with some live bacteria left in the media. It'll give you an idea of how things can differ when giving the cycle a head start.