With a Penn Plax Cascade filter, there’s a floss pad that removes fine particulate matter while the activated carbon media removes toxins and impurities from your aquarium water. These two systems help establish a cleaner environment for your aquatic pets. The coarse sponge then facilitates the final filtration stage by providing a large surface area for bacterial growth. The bacteria help to digest waste, excess food and harmful ammonia and nitrates. Your Penn Plax filter is designed for easy setup and use. Follow the included setup instructions, and once everything is secured into place, use the push-button self-primer to start the filter.