When soaking driftwood to remove tannins, does it help to change the water every 24/48 hours? The water right now has a very light coloration like a diluted scotch whisky after 24 hours. I can clearly see the bottom of the pale at 18 inches deep.
Usually when I get rocks/driftwood, I boil it and that removes a lot of the tannins if not all, but those pieces are small and are able to fit all the way or halfway in a large pot.
The bad news is that if your piece of wood changes the water colour to the extent you describe in only 24 hours, I suspect you will be waiting/watching/changing water for a long, long time before the leaching process begins to slow down much...

A study has shown that Tannins are a natural stress reducer for even hard water fish.