Purigen is a unique macro-porous synthetic polymer that removes soluble and insoluble impurities from the water, at a much higher capacity compared to competing products. This is due to its unique spherical and macroreticular design, and its microscopic pores vastly increase its surface area to many times that of a purely spherical resin. Purigen is incredibly effective at clearing haziness, and polishes water to unparalleled clarity. Purigen will change from a pale colour to a dark brown or black when it becomes exhausted. It can also be renewed and used again after cleaning in a solution of bleach and water, which “burns off” the organics that have been removed from the tank. Directions Always rinse before use. Each 250ml of Purigen will treat up to 1,000 L (250 gallons) for up to 6 months. Place inside a fine mesh filter bag and place inside the filter, so as to maximise the water flow through it.