Features: -Pond care. -Rapidly removes phosphate and silicate from marine and freshwater aquariums. -Not recommended for phosphate buffered freshwater. -Highly porous for high capacity and bead-shaped for optimum water flow. -Available in 100 ml, 250 ml, 500 ml, 1 liter and 2 liter sizes. - the . Product Type: -Algae control. . Dimensions: -100 ml Weight: 0.21 lbs. -100 ml 5'' H x 4.69'' W x 1.25'' D. -250 ml Weight: 0.58 lbs. -250 ml 4.81'' H x 2.44'' W x 2.44'' D.