Bought less then perfect rock?

[Youngster Dan]

+1 on the 3-4 months.

It's called "cooking" the rock, which is kind of a funny term. I did this a while back to get rid of aiptasia from rock that I bought used. Make sure to keep that lid on, as you don't want any light to reach the rock. Oh, and don't be like me, and be sure to add water to replenish what has evaporated. This process probably kills some good stuff in your rock as well, but I think it is a good way to get rid of some of the nasties.