The Helix Moving Bed Waterfall Filter is for biological filtration only and is meant to be used alongside some other form of filtration, such as an under-gravel grid, bead filter or natural planted bog. Self-cleaning and needs zero maintenance if placed after mechanical filtration. Recommended to use with an air pump (Not included) for increased dissolved oxygen levels. Heavy-duty rotomolded HDPE construction is easy to hide in the landscape. Stainless steel hardware and high quality plumbing parts extend the filter life. Includes 5" Radial Air Diffuser, 3/4" Bulkhead, 2" Bulkhead, and 2" Suction Strainer to protect inlet. Made in the USA.