DRIFTWOOD FOR AQUARIUMS CAN SOMETIMES BE DIFFICULT TO PLACE IN AN EXISTING SET UP BECAUSE DRIFTWOOD NORMALLY FLOATS. BY MOVING GRAVEL ASIDE ,GETTING FISHING STRING AND DRILLING A SMALL HOLE IN THE BOTTOM OF THE DRIFTWOOD , IT CAN BE TIED SECURELY TO THE UNDERGRAVEL FILTER. THIS HOLDS THE WOOD TO THE BOTTOM WITHOUT HAVING TO WORRY ABOUT FINDING YOUR DRIFTWOOD FLOATING ON THE TOP. MAKE SURE IT IS FREE OF MUD AND DEBRIS SO IT DOESN'T INTRODUCE DISEASE TO YOUR WATER. USE NO CHEMICALS. PRESSURE WASHING IS THE BEST WAY. UNLESS IT IS ALREADY DONE FOR YOU. THANKS AND GOOD LUCK WITH YOUR AQUARIUM!