I boiled my wood, and that does work. It took many pots of boiling water, and I would dump the "brown" water add more and continue boiling, until the water was relatively clear. To this day (3 months later) when I do a water change, I can see the water taken out is still a bit brown, but you don't notice it in the tank, it looks clear. It is not harmful for the fish, and likely has some benefit for them, but not nice looking when the tank gets too brown. Without boiling, you're probably looking at brownish water for a very long time.