Reef•Basis - Captiv Phos Fe is a supreme quality, granular ferric oxide based filtration medium particularly selected for sensitive aquarium environments. It is designed to remove free phosphates and silicates that can act as a fertilizer for unwanted algae or diatoms, directly from the water and will also remove phosphate bearing dissolved organics. It will not kill algae and does not contain any algaecides. It is safe for all marine and freshwater life. Use in aquarium keeping. Phosphates enter the aquarium primarily through tap water additions for evaporation or water changes, food addition, particularly brine shrimp, some other frozen foods and use of inexpensive carbon. Silicates enter the aquarium primarily through tap water (natural water contains silicates and water companies add sodium silicate to control equipment corrosion), poor salt mixes, and also improperly filtered additives made from tap water. Phosphates and silicates should be first controlled by the use of water made by reverse osmosis or
