Seagel is a blend of matrixcarbon and phosguardr r matrixcarbon is an ultracapacity carbon for the removal of organic and color impuritiesr phosguard is a powerful remover of phosphate silicate toxic metals and acidsr r both components are bead shaped for optimum water flow characteristics and penetration the components enhance each other and are ideal for reef and marine user may also be used in freshwater that is not phosphate bufferedr directions use 500 ml for each 300 450 l 80 12