This DIY Kit will allow you to build a (3 x 11.5m pond) at 3 ft deep. Equating to a total of (34,500) litres.
 
Pond kit Matic 34,500 litres -
Pond Dimensions: Length 3m; Width 11.5m; Depth 1m
Filter Kit: ScreenMatic 145,000 set
Liner: Greenseal 1mm thick 6m x 14.5m
Underlay: 250 gsm (white)
Total Litres: 34,500 (Approx)
Max Stocking density: 34 x Koi or Larger species
Additional equipment included: Discharge pipe 110mm x 1m / 110mm 90 degree elbow x 1 / Medium
Duty 1.5” hose x 15m