Low Tech Driftwood leaching tannins

[BrokeCurmudgeon]

I placed a piece of Mopani wood into my Fluval Edge 46l tank. I soaked the wood for a week changing the water every few hours until the water was relatively clear. It has now been in the tank for two months and is still coloring the water so that I have to do water changes every other day. Worse than before going into the tank. I am looking for some collective wisdom and advice. Thanks