What to Use as Pond Filter Media

Choosing the right filter media for ponds and aquariums can be difficult. Many options are available to the consumer, and with such an array of choices it is easy to get lost in them. Luckily enough, just about any filter media on the market will work well as a base for water-cleansing, beneficial bacteria, as well as to strain out large pieces of organic matter.

  1. Naturally Occurring Media

    • Organic filter media can be composed of rocks, soil, sand or any other natural (fish-safe) components. Porous rocks are usually used as they provide ample surface area for good bacteria to grow. One of the upsides of using such items is that they can often be found in your backyard.

      When choosing rocks for filter media, it is best to use types that will not alter the pH of the water. To test rocks, add them to a bucket of water that was previously pH-tested, allow the rocks to soak for a week or two and test the levels again. If the pH remains the same, the rocks are fine to use. An alternative is to add a few drops of vinegar to the rocks in question; if they fizz, they will alter the pH of your pond.

      Play sand is an alternate filter media. Sand is cost-efficient and good for growing plants in when setting up a biological filtration system. Use a few inches of sand to cover a more organic mix of leaves, moss and clay. The sand keeps the base layer from floating and clogging intake valves.

    Batting, Plastic, Ceramic and Glass Media

    • Batting, ceramic, plastic and glass are all used as filter media in ponds and aquariums.

      Using batting (the synthetic stuffing in most pillows) provides ample surface area for bacteria as well as a fine ̶0;weave̶1; for catching large bits of organic debris from the pond's water. To clean the batting remove it from its holding tank and rinse it in a bucket of pond water. Do not use tap water as it could contain chemicals that will kill any good bacteria.

      Plastic, ceramic and glass will give a decent surface area for bacteria, and if the intake valve is placed where the water must rise through the media, they will strain debris as well. A combination of these materials is effective in filtering a pond or aquarium.

    Activated Carbon

    • Activated carbon is best used to remove medications from the pond. Copper-based additives are deadly to invertebrates, and carbon can clean out the additives before you stock shrimp, clams and snails. It is also good at keeping the pond water clear.