The foam cartridges found within the Aqua One 103 Series internal filter perform the dual functions of collecting solids and acting as a home for beneficial bacteria. The 103 internal filter is used in later model AquaStart 500 aquarium.
◾ Controlled porousity foam
◾ Designed as a perfect home for aerobic bacteria
◾ Cartridges may be rinsed out several times
◾ Change every 3 months to maintain filter performance