Stoney River Black Aquatic Sand is a popular substrate for freshwater and marine environments. Stoney River will not change PH and is non-toxic and durable. We recommend using one to 1.5 pounds per gallon of tank capacity. To Rinse, place the sand in a large bucket, fill with water and allow the water to overflow. Some of the fine particles will float initially and should eventually sink in your tank, especially when using an outside box filter. Occasionally there is a small amount that will continue to float, these particles can be easily removed with a fish net.