I am shocked at how much tannins the 2 small pieces of wood I have are releasing. I bought them at the LFS. I soaked it for 1 month, changing the water every 3-4 days, before i put it in the tank. I threw it in the tank and after 8 days the water was so dark I could hardly see the back wall of the tank. I did a water change and then it started turning the water dark again. Last night I boiled both pieces of wood and it turned the boiling water so dark it looked like black coffee. I put it back in my tank today and surprise! its turning the water dark again. anything else i can do? i don't mind slight discoloration but i don't want it getting darker everyday to the point where I am forced to do water changes every week. The pieces of wood are in a 75G and soaking wet they prob weigh 3-5 pounds each....so not that big compared to the size of the tank. thanks.