Clear X powder is a magic product from Dymax. its clears the water quickly and effectively. It makes the aquarium water crystal clear and can maintain the crystal clear effect for up to a month. Suitable for both freshwater and marine aquariums. Safe for aquatic lives and invertebrates. It comes in a pack of 5 sachet, 1 sachet is 5gm and it can treat 500 L of aquarium water.