Fumed silica is the most important inorganic oxides used for the high performance porous inkjet media due to its high ink absorbing capability, hydrophilicity, and ease of modification. To improve the water fastness of the anionic dye, the surface of the fumed silica need to be modified from negative charged to positive charged. In this paper, different methods to convert the surface charge of fumed silica, and their advantages and disadvantages will be discussed. The chemicals used to treat fumed silica include aluminum chlorohydrate (ACH), aminosilanes, mixture of ACH and aminosilanes, and addition of cationic polymers. A novel process has been developed to treat fumed silica with silane coupling agent in water and their advantages will be discussed. The image quality, the stacking permanence, the durability, and the water fastness of the porous inkjet media comprising these fumed silicas will be compared and discussed.