Cascade Koi & Aquatics have been selling Marina gravels for many years and use them in store for dry and wet displays. Create a colourful aquascape in your aquarium with Marina Decorative Gravel. The gravel is epoxy-coated, which makes the gravel inert and prevents any adverse effects on water chemistry. Research shows that epoxy-coated gravel provides an optimum surface for the colonization of beneficial bacteria, which in turn provide biological filtration for clear and healthy water. The gravel is dust free and is available in a wide variety of colours.