JBL Clearmec PlusFilter media to remove nitrite, nitrate and phosphate from the aquarium water. Key Features: Removal of nitrite, nitrate and phosphate from the aquarium: filter medium for the use inside aquarium filters. To use: material is already packed in two filter bags. Insert into filter. Withdrawal of nutrients from the water: counteracts excessive algae growth. 600ml for 150 to 300 litres freshwater.