The filter material determines the quality of the filtration and the cleanliness of the water. The right combination of filter materials is essential. VT offers four different filter materials with filter net in a handy bucket to clean 3000 liters of pond water. Fill the material into the supplied filter net and rinse it several times with plenty of water. It can then be filled into the filter.Filter lavaThe coarse structure of these chemically cleaned filter lava lumps makes them a particularly suitable filter substrate for all types of pond filters. Many billions of microorganisms will soon colonize the many openings in this porous material, resulting in ideal purification of the pond water.Pond filter charcoalThis active filter carbon is excellent for removing the finest dust particles from the pond water. If you replace the pond carbon once during the season, you can always be sure of having clear and healthy pond water.Zeolite filterZeolite is a natural rock that has the ability to bind nitrates and phosphates. This property also makes zeolite an important filter medium for keeping the pond water healthy and algae-free. If you replace the zeolite once during the season, you will keep the pond water in optimum condition.Filtra-SubFiltra-Sub is a particularly suitable material for filtering coarse dirt particles out of the water. The coarse pores do not clog quickly and allow the purified water to pass through easily. Due to its structure, this material is also an ideal colonization material for microorganisms.