Thanks, Ric. I was just about ready to pull them out of my pond this weekend. You saved me some work and some fish a home base. The limbs I put in my pond are not hollow by any means. They are not fresh-cut either. Like I said, they have been on the ground for at least 14 months. But, what does tannin look like? How does one tell if branches are the culprit? How do people get into the problem with tannins? What should I look for in the building of future wood piles to avoid any tannin problems? Still learning.