Driftwood: Unsinkable
I didn't want to take it off its base and screw it to a heavier piece of slate as I had no guarantee that would add sufficient enough bottom weight. I also didn't want to drill for fear of splintering the wood.
I got seven pieces of slate and simply layered them across the marble base once I held the wood down in the tank. Not only does this securely anchor the driftwood piece, as you can see it looks great. More natural.
Josh
http://joshday.com