Use 60 mL (1/4 cup) for every 200 L (50 US gallons) of saltwater or 400 L (100 US gallons) of freshwater. Leave the media in place for 4 days, and then test the water quality for phosphate or silicate concentrations. If the concentration of the component you are trying to decrease has not dropped to around 0.02 mg/L, then it is time to replace the media, otherwise leave it in place until the chemical levels once again begin to elevate. As long as concentrations of phosphate and silicate remain under control, the product will not be exhausted. Over treating is not recommended. Seachem PhosBond is not an exchange resin and does not release anything into the water, providing security and peace of mind for aquarists everywhere. The media will not leach phosphate or silicate back into the water and with incredible durability, may be removed, dried, and used continually until it is been fully exhausted. For greater ease of use, the continuous use of small quantities of the media yields significantly better results than inconsistent use of larger quantities.