Removal of nitrite, nitrate and phosphate from the aquarium: filter medium for the use inside aquarium filters To use: material packed ready for use in two filter bags. Insert in the filter at the penultimate position, in front of the last fine filter material Nutrients are bound to the filter material and no longer released. When the levels of the problem substances rise again: reapply JBL Clearmec plus 600 ml = 450 g for 150 to 300 litres of fresh water Package contents: 2 ready-to-use bags with filter materia