Ummm, I don't think I would use ocean driftwood in a freshwater tank. As far as I know, it will contain salt for a long time. You can get driftwood from lakes and sometimes rivers too. I don't know how long to soak it for, and I am too lazy to do it myself lol. I don't have driftwood in my tanks yet. The next thing I am putting in is deer antlers! WHOO HOO!
I got my rocks from a creek close to my house, and I boiled them like an idiot. I didn't even think about them exploding if they had a possible crack lol! I think you soak them in a bleach solution in a bucket for a few days. If you want, you can get some, and pour some vinegar on them. If it bubbles, don't put it in your tank. I stuck with shale/slate and granite. If the rock crumbles, I would not put that in either.