boiling the driftwood will get rid of not only the tannin but most of the bad stuff on that piece that you don't want in your tank... It also helps with water logging it quicker so I hear..
OR - I could just cut my losses. The wood was only six bucks. I'd rather spend thirty bucks on a higher quality piece of wood and save myself all of this hassle.Mopani is the worst for tannin leaching....Once it's been in the tank for a few weeks or months (after extensive boiling) The leaching becomes unnoticeable.