Ditto wat UKCATS said. The water will not do any good to shorten the cycle. Nor will aged but freshly mixed, well airated, temperature adjusted water do ant HARM to the cycle. Either in my opinion will be fine for the "transfer" You MAY get a small spike just from stirring the stuff up as well as exposure to air. But if you pull it from one then replace it right into the other. No spike. You do need to be sure and continue to feed the bacteria though. Adding any kind of fish food, a raw shrimp or even fish will help it to carry on. Dont do much of any rinsing of the rock, dust it off some with a turkey baster if you like, then just pull it and replace it. Sand is the same, you can however, shift the sand slowly to one side. Piling it up a little, so the water runs out and then scoop the sand out and place it in the new tank. This will remove some of the decomposing stuff on it as well as keep the new tank from getting quite so stirred up.