live rock

[pirate]

Well I bought 50lbs of live rock that is full of aiptsia (sp). Currently its sitting in my bath tub in fresh water, I am going to kill the rock. I dont want the aiptsia going into my new tank. I relly dont care if its live as i got it at a good price and I already have live rock in the new tank for seeding purposes.
So how long should I leave it in the fresh water to make sure that everthing is dead? 1-2 days? should I boil it after to make sure after the fact..
Any other way to kill the rock? Its going to go into a reef tank when I'm sure that nothing bad is going to come in with it.
Thanks