Sand is suitable for decorating table centerpieces with candles, favors with a beach theme such as message in a bottle or anything else that needs a little flourish of sand. A White aquarium substrate can add a great contrast in colors from other rock or decoration in your tank; White will really stand out against bogwood and slate rocks Gravels are one of the most important parts of the aquarium as they keep water fresh and healthy long time by absorbing all the waste Suitable For Freshwater Tropical; Cold Water & Marine Aquarium Tanks and This Provide a Very Healthy Environment For Plant & Fishes. Empty the sand in a bucket and wash till all the dirt is out. Then put in aquarium.