Koi Pond Sand Filter Information

High rate sand filters are becoming increasingly more popular with koi enthusiasts as both mechanical and biological filtering devices. The fine silica sand keeps water crystal clear while allowing for a large colony of beneficial bacteria to grow on the large surface area of the sand. These are relatively low maintenance filter systems and are relatively cheap when compared to multi-chambered biological filters and other mechanical filtration systems.

  1. Clogging

    • One of the drawbacks to using sand filters is that they are designed to be used with chemically treated water, as with swimming pools and other such bodies of water. Because koi ponds are generally not chemically treated, the sand filter device will often clog up the filter system. Although using fine grain silica sand is preferred in these devices due to the ability of the sand to filter out even the smallest of impurities, to prevent having to backwash the filter every few days, replace the sand with small aquarium gravel. This will also help the flow rate of the filter.

    Pressurized System

    • Another benefit of using a high rate sand filter in a koi pond is that the system is pressurized. This means that the placement of the filter is no longer dependant on gravity and the unit can be placed just about anywhere, including partially buried. This enhances the aesthetic value of your pond environment.

    Uses

    • Sand filters work best in smaller pond situations due to the relatively small surface area being offered for water movement. Larger ponds mean more impurities that will be strained out of the water and require that your filter be backwashed more often, even up to once per day, in order to prevent clogging. In larger ponds, this drawback can be overcome by installing another filter or two parallel to the first.

    Anerobic Bacteria Buildup

    • In the event that the sand filter must be shut off for more than 24 hours, it must be flushed before it can be restarted. This is because shutting off the filter traps water in the filter device. This water quickly becomes oxygen depleted and will encourage the grown of anaerobic bacteria. This bacteria, in large volumes, can be toxic to your fish and turning the filter back on without flushing will push this toxic water back into your pond.

    Economical

    • For small koi pond keepers, sand filter devices will be one of the most economical options when it comes to pond filtration. This is because the mechanical filtration is far better than most other mechanical filtration devices on the market today and the sand bed will also serve as a biological filter, eliminating the need to purchase more than one filtering device. Sand has been shown to polish the pond water and make it sparkling clear.