The M70 gravity return FB unit will cater for heavy stocked ponds up to 7,000 gallons (31,500 litres), and is best served from a high pressure pump offering around 830gph (like Blagdons Amphibious P4000) - with final operational flow rates of around 700gph. nThis unit is approx 1000mm high (40") with a 110mm (4") diameter core containing 6kg of silica sand, together with standard 38mm (1.5") inlet pipe manifold including a Cloverleaf Side Valve on the inlet side, together with a non return valve. nOutlet/gravity return is for 50mm (standard 2") rigid pipework. nThe M70 will support up to 100kg (220lb) of fish load.n