i actually have a piece in there... its in the middle of the tank though, the frog actually moved it there. He loves to hide under it in the sand. When he darts in or out from under the piece of driftwood, you can see it rocking back and forth lol. I just tested the PH, and since its mostly bottled water, it was like 6. I did a partial water change with my tap, which is actually like 7.6. Im about to set up a 20g for a young albino i plan to get.