QuietFlow LED Pro Aquarium Power Filter - 20 The Aqueon QuietFlow LED Pro Aquarium Power Filter 20 features a patented 5-stage advanced filtration system that includes mechanical, chemical, biological, wet/dry components and a filter pad. The LED cartridge change indicator is set off by rising water in your filter. Letting you know that your filter is clogged and it is time for a replacement. Great for use in both freshwater and saltwater aquariums, it is designed to ensure crystal clear water, increased oxygen levels, and healthier and more active fish. Stage 1 - Biological - The QuietFlow LED Pro's patented filter cartridge features dense floss that effectively traps dirt, debris, and particulates from your aquarium water. Stage 2 - Chemical - Water is forced through the QuietFlow LED Pro's filter cartridge where the premium activated carbon effectively removes toxins, odors, and discoloration. Cartridges contain 25% more carbon than competing brands to help you maintain a flawless aquatic display. Stage 3 - Biological - The QuietFlow LED Pro features a patented biological grid that provides a large surface area for the propagation of bacterial colonies. As water passes through the bio-holster, toxic ammonia and nitrates are actively removed by these beneficial bacteria. Stage 4 - Wet/Dry - Water flows into the diffuser grid which removes additional toxins. It also increases dissolved oxygen levels, promoting increased fish activity and vitality. Stage 5 - Filter Pad - The replaceable specialty filter pad adds extra filtration to water prior to returning it back in the aquarium. The Aqueon QuietFlow LED Pro Aquarium Power Filter 20 features a new internal pump design. It dampens noise for near-silent operation, maintains consistent flow rates, and eliminates messy leaks. Since the UL listed pump is fully submersed, there is no need for priming at the time of initial filter setup, or subsequent to routine cleanings and power interruptions. Designed with aquarists and their fish in mind, the Aqueon QuietFlow 20 is a highly affordable and equally capable filtration system. It features a flow rate of 125 gph, making it suitable for use in aquariums up to 20 gallons in size. Uses size Large replacement filter cartridges (1 FREE cartridge is included to get you started). 7.625" x 4.75" x 8"