• protecting the pump from debris
• breaking down dangerous fish waste
• trapping some suspended particles from the water
• removing some dissolved waste from the water
• reducing algae growth by removal of nutrients

Types of Pond Filters

Intake Filters also referred to as prefilters are usually small (perhaps 3x3x6 inches or so) blocks of open-celled foam that often come in the box with the pump. These are far too small to be effective at waste removal or reduction, and serve only to prevent pieces of debris from being sucked into the pump’s intake and stopping or damaging the pump itself. Advantages: inexpensive; easily removed and rinsed clean; output of pump can still be used to run fountain or waterfall. Disadvantages: small surface area means they plug with debris quickly; often need to be rinsed daily or even more frequently; do not improve water quality significantly. Things to Look For: very coarse foam for good flow; firm attachment to pump; multiple filtering surfaces so a single leaf cannot block flow.  Also the use of a pump sock helps the frequency of how often you have to clean as they have more filtration material that has to become clogged before having to clean.

Submersed Filters are generally larger and more versatile than intake filters. A reasonable unit for a small pond might have a surface area of a square foot or more, and may use a variety of filter media including coarse and fine pads for mechanical filtration, carbon or zeolite for chemical filtration, and perhaps some sort of plastic or porous stone media for biological filtration. Many units can be installed on either intake or output side of the pump, but are most commonly connected to the intake where it protects the pump as well as cleans the water. Advantages: improve water quality as well as protecting pump; may go days to weeks between cleaning; optional filter media may be added for special purposes; pump output may still be directed to water features. Disadvantages: pondkeeper may need to wade into pond to retrieve filter for cleaning; much waste from filter may spill back into pond during cleaning; take up valuable space inside pond. Things to Look For: easy disconnection from pump; large surface area; room for several different media; filter media compartment recessed enough that waste isn’t spilled when removing from pond.

External Filters which can be either gravity flow (filters that need to be placed above the area they are flowing into as the water flows out only as fast as it flows in and cannot push water upward) or Pressurized (filters that are under such pressure that they can be placed at ground level and push water up to a waterfall, etc.) are generally the largest of pond filters, and are located above ground (some may be partially buried) somewhere near the pond itself. Water from the pump’s output enters the top of the filter, trickles through the filter media, then drains out the bottom port. External filters may be operated with a variety of media, but generally use large sheets of foam for mechanical filtration with several gallons of plastic or porous stone biological media underneath. Many operate on the “wet/dry” principle used on high-tech saltwater “reef” aquariums, in which the biomedia has water continuously running over it but is not submerged. Advantages: improve water quality; may go days to weeks or even months between cleaning; most efficient form of biological filtration supports greatest fish load; optional filter media may be added for special purposes; above ground installation makes unit easy to clean.  Things to Look For: internal bypass that allows water to continue to flow if filter clogs; large surface area; room for several different media.

Filters may be used in combination to take advantage of each filter’s strong points. A common setup is to attach a submersed filter on the intake side of the pump, filled with coarse media to prefilter and protect the pump, and also an external filter on the output side, filled with finer media to catch smaller particles and biomedia to improve water quality by reducing ammonia and nitrites. Such a complete system not only provides the best filtration, but also can result in longer times between cleanings.

Sizing the filters Regardless of the pond size, a small filter is better than none, a medium better than small, and large better then medium. The bigger a filter is, the more waste it can catch or process between cleanings, and the more fish can be safely maintained The trade-offs of course are that bigger filters cost more and take up more space. Another concern is to match the filter to the pump’s output. An undersized filter will either restrict the water flow, or worse, leak water from the system. In such cases, a bypass should be installed to divert water to another water feature, or better still to another filter.

Filters with built in UV Clarifiers  THESE FILTERS combine UV clarification and biological filtration to guarantee crystal clear, purified water. Water passes in front of the UV light, which causes algae to clump and die. Then, the filter sponge traps algae clumps and other debris, allowing clean, clear water to enter the pond. It is a well known fact that a UV clarifier helps to keep your pond crystal clear and free of algae blooms so prolific that it turns your water a "pea soup" green color.  It is also a reminder that a filter including a UV clarifier are cheaper than to purchase a filter and a stand alone UV clarifier unit separately. Scroll down the page for more information on how valuable a UV Clarifier can be.

To select the appropriate filter or filters for your application, please visit our  "FILTERS" section from our homepage. As always, if you still have questiong or concerns before purchasing the correct item(s), please feel free to contact us at 1-800-245-5814 to discuss.  

A pump will keep the water circulating. Connecting a fountain or waterfall to the pump's discharge will oxygenate the water. To choose the correct pump size, first determine the volume of the pond. If the pond is square or rectangular, then multiply the length x width x depth (all in feet) by 7.5. This will give you the gallonage of the pond. For round ponds, multiply the top diameter x bottom diameter x depth (all in feet) by 5.7. This will give you the gallonage of a round pond. Recirculating the volume of pond water should be hourly in the average pond (500 gallon pond would require a 500 gph pump). More frequent turning of water is required if pond is: overstocked with fish, exposed to more than 6 hours/day of sunlight, or tropical climate locations such as Florida, Southern California, etc.  To extend the life of your pump, a prefilter or screen should be used to prevent debris from clogging the intake of the pump, thereby restricting the flow. Remember that flow rate of pump is reduced when water is lifted out of the pond to a waterfall, filter, or fountain. The flow rate at the height of lift should be used in determining the pump needed. You may find that the recommended gph pump is not enough if you plant to have a waterfall that is more than 10 inches wide. Generally for a waterfall you will want 100 - 150 gph per inch of width of the weir (the portion that the water spills over). This amount will vary depending on how smooth or rough the weir is. If you want less than a full flow then less flow is acceptable. You will also need to consider your filter and ultraviolet sterilizer (UV) to make sure that you are moving the right amount of water for these devices.

If your filter or UV has a maximum flow that is less than your required flow rate for good circulation of your pond water, then you will need to divert some of the water around these devices and back into the pond. This is accomplished by adding a tee fitting in the pipe coming from the pump and before your filter and/or UV. A ball valve is added between the tee and the filter. Another ball valve is installed on the other output of the tee. This will allow you to control the amount of flow going in both directions allowing the proper amount of flow from your waterfall.

Submersible vs. External

Before you choose your pump however, there are other things to consider. Should you use a submersible or an external pump? Submersible pumps are usually less expensive and easier to install. However, some may cost more to operate and usually don't last as long as external pumps. There are a lot  of variables in determining the longevity of a submersible pump. How dirty the water, how often the pump is cleaned, and if it is operated continuous or intermittently will all influence the lifespan of a pump. External pumps are generally very energy efficient and long lasting, but involve a little more plumbing and you will generally want to find a way to disguise the pump from view. It is often good to compare the warranty of the pumps you are considering as this can give an idea of which pump will last longer. We have found that on average a pump will last 2-4 times the stated warranty period. A pump that costs twice as much as another but lasts 3 times as long will be a better value.

KEEP IN MIND:

A SUBMERSIBLE PUMP SHOULD NOT BE PLACED ON THE BOTTOM OF THE POND, RATHER ELEVATED IN WATER. THIS PREVENTS THE POND BOTTOM DEBRIS FROM CLOGGING THE PUMP, AND DECREASES THE HEIGHT THE PUMP MUST LIFT THE WATER.

Step 4: Calculating Operation Expenses

You can determine the operating cost of any pump by using this formula: amps x volts divided by 1000 x KWH cost x 24 hours-a-day x 30.4 days-per-month = cost per month. If the pump is rated in watts instead of amps use this formula: watts divided by 1000 x kWh x 24 hours-a-day x 30.4 days-per-month. KWH is the kilowatt-hour cost, which you can get from an electric bill or by calling your local electric company.

Most of the pumps we offer can be matched up with most of the filters we offer - with a few fittings and tubing. Pumps and filters can be purchased separately or you can purchase a kit that includes the appropriately matched pump & filter - and sometimes accessories such as fountain heads, fittings, tubing, etc. MOst of these kits include a submersible filter - that does provide some mechanical and biological filtration - but its primary purpose is to pre-filter the pump.

To select the appropriate pump for your application, please visit our  "PUMPS" section from our homepage. As always, if you still have questions or concerns before purchasing the correct pump, please feel free to contact us at 1-800-245-5814 to discuss.