aquarium wood

Dear Sir:

	After finding your name over the Internet, I was wondering if 
you had any suggestions on how to "sterilize" or "cure" a piece of wood 
for an aquarium.  Recently, I cut a hollow cypress knee, boiled it, and 
then peeled off the bark. I then placed it in my 55 gallon tank and it 
turned the water brown.  Do you have any suggestions for making a piece 
of wood suitable for an aquarium?

Thank you.

Chad R. Hutchinson (chutchin at teclink_net)