Dupla Marin Siliphos 840ml Dupla Marin Siliphos is an iron-based phosphate and silicate removal media. Removal of these compounds within the aquarium is essential in combating slime algaen growth. Dupla Marin Siliphos can be used in any filter model. Binding Properties 180ml of Siliphos will bind 7,500mg of PO4 and 1,500mg of SiO2 360ml of Siliphos will bind 15,000mg of PO4 and 3,000mg of SiO2 840ml of Siliphos will bind 35,000mg of PO4 and 7,000mg of SiO2