5l biofilter (pressurised) with an 8W U/V combination filter. Typically 20 to 60l/min flow rate and good for smaller ponds up to a maximum of 2,500l stocked at hobbyist levels of fish. Bio filters pond capacity is indicative only – if unsure always buy the next biggest version. You can never ‘over do’ biological filtration, and you never want to ‘under do’ it either. Includes around 80 bio balls.