Frequently Asked Pond Equipment Questions

Q. What type of pump should I use?

There are a number of considerations when choosing a pump:
  1. Submersible or external? Most pond owners use a submersible pump. The pump is placed in the pond or in a skimmer and is always submerged.
  2. External pumps require piping through the pump liner for water to flow into it. The pump is located outside of the pond. External pumps and filters can be hidden by plantings, or in a small building, which in itself can add to the overall aesthetics of your water garden.
  3. Pre-filter - Many pumps come with pre-filters to keep the pump from clogging with dirt and debris. Auxiliary submersible pre-filters can be attached to pumps not having pre-filters. The TetraPond® Water Garden Pumps series have attached pre-filters.
  4. Debris Handling Pumps - These pumps resist clogging by using an open-faced impeller design that can pass larger debris without clogging. No pre-filter is needed for these pumps. These pumps are great for minimizing maintenance. See TetraPond® DHP debris-handling pumps.
  5. Energy efficiency - Since water gardening pumps are used 24 hours a day, 7 days a week, you should consider their energy cost. Look at the pump packaging or talk to your retailer about the energy requirements of the various pumps available. Tetra Pond pumps range from 8 watts to 260 watts depending on their size.
  6. Warranty - Choose a pump with a strong warranty. All TetraPond® pumps come with a two- or three-year warranty.
  7. Size of the pump (see next question and answer).

Q. What size pump should I use?

The pump size you choose (pumping capacity in gallons per hour or gph) is based on the size of your pond, your filter capacity and the desired size and appearance of your waterfall, as well as other water features such as spitters and fountains.

Using the 50 percent circulation rule, the pump should circulate the entire volume of the pond at least every two hours. So, if you have a 1,000-gallon pond, you need a pump that will discharge back to the pond at least 500 gph. When in doubt, purchase a slightly more powerful pump. You can always slow or divert the flow of a pump, but you cannot increase it.
Water flow and head pressure:
To choose the proper size pump for a waterfall, you first need to understand pump head height, or the water pressure generated by a pump. The maximum pumping height is the height a pump will raise water straight up resulting in zero gph of water flow at the top. As the height of any pump discharge increases, the flow will decrease.
Calculating pump size:
To calculate the pump size for your waterfall, decide the width of the spillover you want and determine the vertical distance from the waterfall to the pond surface. Every inch of spillover width requires about 100 gph of water flow at the height of the waterfall.
See flow charts on packaging for water volume flow specifications at different pumping heights.


Q. What type of pond filter should I use?

There are many types of filters to choose from.

Submersible filters:
These filters attach to or encapsulate your pump. They are usually sufficient for very small ponds, but can also serve as pre-filters for pumps to prevent clogging.

Gravity discharge filters:
These filters typically provide both biological and mechanical filtration and are placed outside the pond. Since the water discharges by gravity back to the pond, the filter discharge must be positioned above the pond water level.

Waterfall filters:
Waterfall filters are a type of gravity discharge filter. The water is typically pumped through the bottom of the filter; the pond water then flows through filter media and spills over the filter as a waterfall back into the pond.

Pressure filters:
These filters can be positioned anywhere around the pond. Since this sealed filter is under pressure, the filter may be buried and the flow discharged uphill to a waterfall or stream. These are easier to conceal than most gravity filters. Some pressure filters, such as the TetraPond® Bio-Active come with back flush mechanisms to make cleaning easy, as well as integrated UV clarifiers for controlling green water algae.

Q. What is mechanical filtration & biological filtration?

Mechanical filtration is the removal of fine particulate in the pond. The pump forces water through media such as foam, matting, or plastic beads. Particles are trapped by this filter media. This type of filtration also helps remove clumped, dead algae.

Biological filtration converts harmful ammonia into relatively harmless nitrates by way of the nitrogen cycle. Biological filters contain media such as plastic balls or rings that have massive surface areas for beneficial bacteria to colonize. This beneficial bacteria converts harmful ammonia into relatively harmless nitrates by way of the nitrogen cycle. Water containing impurities comes in contact with these beneficial bacteria, consuming the impurities and discharging relatively harmless nitrates. The nitrates can then be absorbed by plants in the pond.

Many filters, such as all of those offered by TetraPond®, contain both mechanical and biological filtration.

Q. How should I clean filters and how often?

The methods for cleaning a filter will vary from filter to filter. Consult your owner’s guide for specific information, but here are the basic guidelines:

Don’t use tap water to clean filter: You should not clean your filter media with tap water. Tap water contains chlorine and chloramines that can kill beneficial bacteria colonies. Instead, use a bucket of pond water which should have already been de-chlorinated with a product such as TetraPond AquaSafe®.

Reduction in water flow: Should you see a decrease in your water flow, it may be a sign that your filter needs cleaning.

Filter cleaning intervals will vary greatly due to the season, type of filter used, the amount of debris entering the pond, amount of fish waste, etc. You will generally need to clean your filter pads and/or backflush your power filter during the hotter weeks of summer when bacteria, sludge and algae accumulate the most.

Q. What is a bog filter?

A bog filter is a basin adjacent to the pond that contains stone, gravel and bog plants. Water is pumped from the pond into underground pipes that disperse the pond water under and upward through the bog. The water is filtered as it flows upward through the stone layers. Nutrients are absorbed by the bog plants and the water overflows back into the pond.

Q. Should I have a UV Clarifier?

The most common complaint of new and experienced pond enthusiasts alike is "green water." Green water is caused by blooms of single-celled algae, which not only cloud the water and obscure fish viewing, but also rob the water of valuable oxygen and release harmful pollutants. These organisms are so tiny, they pass through even the finest filter.

UV clarifiers are extremely effective at combating green water algae. If green water is a recurring problem for you, then a UV clarifier will be a welcome addition to your pond.

UV clarifiers use ultraviolet light to destroy the reproductive ability of suspended algae. Dead algae will clump together into particles large enough to be removed by filtration, leaving the pond cleaner and clearer. TetraPond GreenFree™ Clarifiersr usually remove heavy algae blooms within eight days and keep the pond algae-free.

Q. Will a UV light also kill bacteria?

UV clarifiers do kill bacteria, but for most pond owners, there is no need to eradicate bacteria in the pond by using a powerful UV light to sterilize the water. The TetraPond GreenFree™ UV clarifier will keep the pond algae-free without destroying the beneficial bacteria.

Q. When should I change my UV bulb?
The TetraPond® GreenFree™ UV clarifier bulbs should be replaced after 11 months of continuous use. In most parts of the U.S., the UV clarifier is used only five to six months a year, so it should be replaced every two years. Please know that even if the bulb glows after 11 months of use, its effectiveness against controlling algae will have diminished dramatically.

Q. Where can I get a UV sleeve, UV inlets, filter pads, etc?
Check out our online store for replacement media and parts.  You can also check out the store locator. Or you can call us directly at 1-800-526-0650, 7:30-5:30 (Eastern) Monday through Friday.

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TetraPond BioFilters for optimal pond biofiltration.