Lower Right Side Are 3 x 4″ Inlets, connect these to the bottom drains/skimmers or pump (for pump fed)
Upper Right Side Is 1 x 4″ Waste Outlet
Lower Left Side Are 2 x 4″ Outlet Use For Gravity Fed, this is where you install the return pump(s) However if use the unit as Pump Fed, these 2 holes need to be plug, please use the top left 2 x 4″ as outlets return back to the pond.
Upper Left Side Are 2 x 4″ Outlet Use For Pump Fed, this is where you install PVC pipes for water flow back to the pond, the outlet must be above the water. However if use the unit as Gravity Fed, these 2 holes need to be plug, please use the lower 2 x 4″ as outlets return back to the pond.
Small Pipe in the middle is use for water drainage
Back side of the unit is air inlet, the 1″ coupling adapter is included (zip tied to the air line)