Shocking a system?

[digital-audiophile]

OK, So I finally have my 60 up on a stand, I have it shimmed and the plumbing is all dry fitted and just waiting to be glued.

My question is : Existing sytem is a 90G plumbed into a 40G sump (approx 30G of water in it) now if I fill up the 60 with new SW and flip the switch on the pump am I running the risk of shocking the sytem. Should I say over the course of 2 weeks during water changes move old system water into the new tank until it is full (I would run with a PW and add live rock from the sump)?