Replacement foam red BioSmart 18-36000 INT

For BioTec 5.1/10.1 and BioSmart 18000/30000/36000. The heart of a filter lies in its filter sponges: Red filter sponges have excellent filtration properties, as they function optimally at a medium water flow rate. This means that small dirt particles are simply trapped in the sponge as the water flows through, thus removing them from the pond water. But filter sponges don't just perform classic filtration; they also provide ample habitat for bacteria. This small biological oasis ensures the conversion of toxins in the pond: Toxic substances are transformed into harmless, but algae-promoting substances (nitrification), which are then converted into naturally occurring gases (denitrification). Together with the blue and green filter sponges, they deliver excellent filtration performance.