The EBF 4,000 Biological filter media offer tremendous
surface area for beneficial bacteria to colonize and grow. The patented media
never needs replacing. This filter is the perfect replacement for the Aqua
Ultraviolet units. This filter in conjunction with the included media is
designed for high flow rates without channeling or adding additional head
pressure. Low maintenance just turn valve system to backwash and clean filter
means never having to mess with dirty mats. The Evolution Bio Filter works great
with low amp, high flow pond pumps.