Above Ground Koi Pond made from Home Depot stuff except the pump (sequence 6000 gph primer series pump). System has complete nitrogen cycle. No war changes needed. Replicates real pond nitrogen cycle. Biofilter made from pot scrubbers and plastic garbage can. Even no backwashing of filter needed. Activated carbon removes hard water contaminants. Under porch in the shade prevents algae growth. Total volume 3000 gallons. Handles 60 small fish and 12 large fish without water changes. Plants remove nitrates. Light is utility light from Walmart ($8) 500 watts. In floor cleaning system made from a jet and inverted floor drain to create suction area. Total cost $2000 excluding fish. Home-made pond DIY.