Aqua-Tech Ultra Quiet Power Filter for 10-20 Gallons helps to remove the toxic ammonia and nitrites from your aquarium s water. This AquaTech Power Filter 10-20 provides filtration in three stages which will keep your fish healthy and water clean. AquaTech Aquarium Filter Cartridges help to clean out the dirt and dust when water passes through it. In the second stage the activated carbon present in this Aquarium Power Filter helps to remove dissolved waste and cleans water which is full of odor. In the final stage the filter provides extra surface area allowing bacteria to grow. This bacteria eliminates the harmful ammonia and nitrates from the water which will protect your fish against these toxins. This filter is available in four sizes. It also provides filtration for aquarium sizes that range from five to sixty gallons of water. It is very important to keep replacing the filter cartridge every month for continued excellent results. If the flow of water slows the filter can be unplugged and the filter rinsed to clean it for better results.