Boiling will leach out the tannins faster. When you put the wood in water, it will turn the water a tea color. To prevent this from happening to your tank, you leave te wood soaking in a large bin or bath tub for a long time until the water stops turning tea color. To speed this up, you boil it. For my wood, I put it in an old garbage pail. I got the biggest pot we had, filled it with water and boiled it. Then, I dumped it in the pail. Kept doing it until the wood was covered up. You might have to put something on the wood to keep it down in the pail. Leave it for a few hours, like do it at night, then again in the morning, so it has time to soak. Then, do it again, and if still the tea color, do it again. Then, you can put it in your tank with something heavy by the base to keep it from floating up. If you have a pot the is big enough to fit the wood, then you can just boil it right in there.