IPW Industries Inc. Replacement gravel for filter tanks. This is a 10 lb bag of garnet gravel that can be used under any filter media. This is enough for a 9" or 10" tank. For a 12 or 13" tank order two bags. Contact us directly for other types of gravel or other filter media needs. Additional Details ------------------------------ Bullet point: SUPERIOR QUALITY: This includes 10 pounds of garnet gravel that creates a perfect under bed support base for any standard tanks. Gravel creates ideal backwash dispersion to increase the effectiveness of your water filtration, softening, or conditioning. Product description: IPW Industries Inc. Replacement gravel for filter tanks. This is a 10 lb bag of garnet gravel that can be used under any filter media. This is enough for a 9" or 10" tank. For a 12 or 13" tank order two bags. Contact us directly for other types of gravel or other filter media needs.