Yep, that's the wood you sent me. Right now I have it tucked under the center brace. I'm hesitant to put anything in the water that may alter the water chemistry like a large rock. I first tried gluing the pieces to small slates of marble but that failed miserably.
From your experience, how long does it typically take for the wood to get waterlogged? I'm anxious to plant the glosso in the sand.
Yep, it's pool filter sand. It was highly recommended by discus keepers on simplydiscus. They say detritus has a hard time penetrating it, thus making it easy to clean.