The Best Koi Pond Filter System 2025 (Reviews & Costs)

koi5000OASE BioSmart 5000 Pond Filter Specifications; Dimensions. 23 x 16.1 x 19.1 inches. Weht. 14.33 pounds. Capacity. 5,000 gallons. Hhlht Features. BiologicalWest Midlands Koi are the UK’s sole stockists of EZ-Pond. These premium fibreglass koi ponds are, without a doubt, the finest on the market.