Pond Filter Selection Guide

Biofiltration

Biofiltration depends on an established colony of beneficial bacteria on the filter media surface, large enough to break down dissolved toxic nitrogenous waste into harmless compounds. (For more information on the nitrogen cycle, see the "Algae control" page in our "Maintain your pond" menu.) The secret to the success of external filters is in their high surface area per cubic foot of filter media, which is ideal for hosting a large beneficial bacterial colony. Solids Capturing Solids capturing (water polishing) is the process of removing suspended solids from water. Suspended solids in a recirculating system are generally small particles of undigested food, bacteria, and algae. These solids tend to reduce the clarity of water and cause problems by consuming tremendous amounts of the oxygen needed by your precious fish! External filters remove the solids from your pond's water in two ways. Physical straining removes larger particles (>50 microns). Finer particles (<20 microns) are removed by a process called bioabsorption - the particles are captured by bacterial biofilm on the surface of the filter media.

Low Maintenance Requirements

In addition to superior filtration, the other big advantage that external filters have over other types of filters is that they are much easier to clean - they typically have some sort of three-way valve and mechanical agitator, so cleaning is a simple back-flush operation once a week or so. This makes your koi or pond keeping much more enjoyable, with less work involved in maintaining a healthy environment for your fish.

Why use external filters in a pond environment? In a natural setting, a pond will typically have an inflow of fresh, oxygenated water from a stream source, and a constant outflow of "dirty" water to a downstream outlet. Your fish pond, however, is a closed environment that constantly re-circulates the water volume in your pond. Therefore, you need to maintain a balance of nutrient-creating pond life - your fish - and nutrient-consuming pond life - your plants and beneficial bacteria colony - to keep your pond's ecosystem healthy. While it is certainly possible to maintain the balance of your pond's ecosystem between plant and fish life, no two ponds - or pond owners - are exactly identical.

You may need the supplemental filtering capabilities of an external filter to balance your pond's ecosystem. Some factors affecting the biological load on your pond are:

 You stock more fish than your pond's capacity can handle; (our general rule of thumb: one inch of fish for every ten gallons of water)
 For aesthetic reasons, you have fewer plants than recommended for your water volume - or no plants at all;
 Your pond is in direct sunlight for a majority of the day, or is relatively shallow and subject to heat buildup from exposure to the sun;
 Your pond is subject to rain water runoff or wind-borne debris, either of which can add significantly to the biological nutrient level.

Which filter is right for you?

We've done the research for you, and offer a broad product line that delivers real value for the price - regardless of your filtration needs. Here's a look at what products we offer - and why:

FluidArt

Long recognized as the "Cadillac" of filtration systems by the koi raising community, the FluidArt product line offers superior filtration when no other biological methods are chosen - for instance, if you choose an inline pump and feed it from a bottom drain. FluidArt's filtration systems, especially the "Ultimate" product line, offer a level of filtration that rivals the best in-line systems used for swimming pools, where water sanitation is a top priority. If you plan on raising koi, there is no finer choice in pond filtration systems. And FluidArt provides filtration systems for ponds up to 22,000 gallons in size!

Oase

With their reputation for supplying products that deliver on their "Living water" philosophy, Oase Filtoclear ® filters provide excellent water filtration combined with low maintenance requirements. With their built-in UV sanitizer, Filtoclear ® is a great filter choice for ponds with minimal plant life, or ponds stocked with fish past the biological filtration capacity of your skimmer filter. Oase products are ideal for backyard fish ponds up to 4000 gallons in size.

PondMaster

Similar to the Oase product line in filtering capabilities, the PondMaster filter line fits the intermediate pond sizes that Oase doesn't offer in their Filtoclear ® product line. And because they offer their product with or without a built-in UV sanitizer, a PondMaster filter can save you money when UV filtration isn't required in your pressurized filter.