I ordered a piece of Mopani online and it looks good so far. There was a small piece broken off (I don't mind, I like the larger piece's shape.) I treated both. The large piece is gonna soak for a lot longer but for now I have the smaller piece in there, using it to weigh down a slice of zucchini. My shrimp are already enjoying the driftwood and are grouped around it. I will update about the larger piece!