This all-in-one has a maximum pump flow rate of 3,000lph – the highest we have seen in an all-in-one unit. This power plus the strength of a 9 watt UVC means we can confidently recommend this item for ponds up to 9,000 Litres (2,000 gallons). Please note if running a waterfall, fountain or other water feature with this product then the filter is only capable of ponds up to 6,000 litres capacity. NOT SUITABLE FOR KOI PONDS. NOTE: UVC bulb included.