I had the exact same question just a few days ago. I live in Canada, and bought malasian driftwood, which in my experience has always been able to sink upon purchase and never float (i have bought around 15 different pieces and had the same result....maybe im just lucky). I bought mine at Petland, but noticed the exact same stuff at Petcetera, and Petsmart, which i know are terrible stores to get fish from, but they have cheaper prices on almost everything, so thats where i would go for driftwood....if you have one of those stores. Happy searching