I have had this filter for my Koi pond for several years and it has been fantastic! Keeps the water clear and healthy. Filter system has always been in an enclosed shed not setting out in the weather. Everything works may need to clean or replace filter media Asking $3,400 obo

The Model AD16000 - Model 4.4C filtration system includes a 2" High efficiency Control Head with 2" ports in/out, with 3 ea. 2" self-sealing unions included. The Model 16000 is used in water features ranging from very large backyard lawnscapes to fisheries, to public aquariums, and the most discriminating laboratory applications. The AD16000 is capable of consuming large amounts of fish waste and neutralizing equally large amounts of ammonia and nitrite from the aquatic environment. The model 16,000 will support up to 330 pounds of fish or other aquatic life in up to 16,000 gallons of water, separating and backwashing huge amounts of solid particulate waste without clogging.

The Dynamax air assisted backwash makes this model extremely efficient in all ranges of waste loading. The high efficiency central diffuser column allows an efficient water flow of up to 6,000 GPH (and maybe a little more) without sacrificing filtration efficiency. As with all other Aquadyne filters the 16,000 comes standard with the Dynamax air assisted backwash system.