I asked in the chatroom about this... but I am interested in adding driftwood to my marine tank. It was on my FW tank before I shut it down for a Discus project. any thoughts?
I'm pretty sure dorkfish is right about it lowering the pH, but I'm not sure that means that you couldn't do it.
I have driftwood in my African Cichlid tank. It is a 60gal with probably 6 pieces of driftwood that are 12-15 inches, for substrate I have 2 inches or so of African cichlid sand that buffers the pH up to 8.2.
My pH has always stayed right at 8.2 in that tank. So depending your substrate and how often you water change (I think most brands of sea salt buffers pH) it might be alright.
Not to mention the fact that there are a lot more little salt water critters that'll eat wood vs fresh. That's why wrecks in warm tropical waters don't last nearly as long as they do in f.w. lakes etc.
hth
chris