This Top Fin Premium Aquarium Gravel comes in a wide array of colors, and assists in mechanical and biological filtration. Choose one or more colors to accent the overall look of your aquarium. Only at PetSmart. Features: Assists in mechanical and biological filtration; Comes in a wide variety of colors Includes: 1 bag of Gravel Intended For: Aquariums Material: Gravel Color: Assorted colors; please see drop down for color options Instructions: Use up to 1.5 lb of gravel per gallon of tank. Rinse thoroughly in cold water before using. Never use soap or detergent. When filling your tank, place a saucer on the gravel and pour water onto the saucer. This will prevent the water from disturbing your layer of gravel. The aquarium gravel will become a home for beneficial bacteria to keep your aquarium healthy. Once your aquarium is established, do not wash the gravel. Just use a gravel vacuum once amonth to clean out loose particles. Caution: Gravel may contain minerals that affect water pH. Monitor your water pH after adding gravel and adjust as necessary to avoid sudden pH changes. Size: 5 Lb. Color: Glow in the Dark.