Advice for tank transfer?

[lastlight]

Thanks guys.

The new rock (if it's like the rock I started this tank with) hopefully won't cycle. As odd as it was my rock from Red Coral didn't cycle...at least not according to Elos.

The old tank will be shut down so I'd prefer to move it all over at once. What's everyone's motive for using some of the old water? I'll ensure the basic 3 match in both tanks. Is the concern ph? Shock from things we don't measure being different in the new water? Or does old water hold magical powers?