To properly maintain fish in a pond, pond hobbyists rely on several stages of water filtration. The most important is biological filtration that will convert the deadly fish waste, ammonia, to less toxic nitrite, and finally to nitrate. This is accomplished by two stages of nitrifying bacteria:
- Utilizes ammonia as a food source and releases nitrite as its waste
- Uses nitrite as their food source and release nitrate as their waste
Nitrate is almost non-toxic and is utilized in plant growth. The bacteria will appear wherever there is surface area. For this reason many pond filters provide a specialized biological media that has a large surface area-to-volume ratio for colonization. This process does take time and can be facilitated by the use of Microbe-Lift or Bio-Boost. To control the development of excessive organic wastes, you can use products like Sludge-A-Way or Bio Sludge Control. The biological filtration stage is the most important to the health of your fish.
Another stage of purifying the water is chemical filtration, usually accomplished by the use of activated carbon, chlorine neutralizers, or even the addition of trace elements to promote plant growth. While the activated carbon is placed in a pond filter, most other chemical filtration products are added directly to the pond water.
Mechanical filtration is also important to our enjoyment of the pond. This involves the use of some type of filter media to physically remove floating debris and wastes in the water. This is typically the first stage of a pond filter and will require frequent cleanings. Filter floss or pads are the most frequently used mechanical filter media. Some pond filters use sponge pads for the mechanical filtration. You simply “squeeze” clean them in water from the pond and re-use. While not necessarily part of water filtration, the use of an ultraviolet clarifier can eliminate the free-floating algae and is often included as part of the pond filter, as with the Fish Mate U/V Bio Pond Filters. With all stages of filtration present in your pond system, the water will remain healthy and clear for the health of the fish and your enjoyment.