Should a Pond Pump Be on All the Time?

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Ponds can add tremendously to your landscape and your enjoyment.  The variety of plants that a pond can support as well as the wide variety of colorful fish, bring a new dimension to landscaping.  Maintaining a pond can be both time-consuming and expensive and many people ask, “Does a pond pump need to be on all the time?”

A healthy pond environment requires moving water.  The pump should run 24 hours a day to keep the water in your pond moving.  Moving water around the clock is critical to:

  • Keep the filtration system operating at peak efficiency
  • Ensure the dissolved oxygen content remains at the proper level
  • Move heavier, suspended material through the skimmer system

Ponds add a new dimension to your home landscape.  Proper maintenance and care of a pond are essential to the health of the fish and plants that depend on the pond water for their survival. I’ll explain how the movement of the water in your pond works with the filtration and aerations systems is critical to the task.

Moving Water – It’s Not Just for the Sound Effects

In many ponds, the waterfall or fountain is a focal point.  The sound of water trickling over a waterfall or dancing back to the water from a fountain adds another level of enjoyment to owning a pond.  But these features are not included in ponds solely for ornamental reasons.

Water passing over stones or through the air dissolves oxygen into the water.  Oxygen in the water is essential for several reasons.

  • Pond fish depend on oxygen dissolved in water just as we depend on oxygen in the air we breathe.  Your Koi and other aquatic animals must have the correct levels of oxygen in the water to thrive.  Keeping water moving by keeping the pond pump running ensures proper aeration of your pond water
  • Like your fish, aquatic plants that grow in your pond require oxygen as well. Proper levels of dissolved oxygen in the water will encourage healthy growth and flowering of your pond plants.  Some aquatic plants need currents around the roots to bring a constant flow of nutrients as well.
  • The filtration system on your pond depends on a healthy bacteria colony to keep the different kinds of fish waste under control.  The bacteria convert the fish waste into substances that your pond plants use as nutrients.  The plants remove the toxic materials from the water keeping your fish healthy and your plants happy.
  • Water moving through your ponds system also carries heavier particles such as tree leaves and other things that can blow or fall into the pond into the skimmer basket.  The skimmer basket keeps this heavier material from sinking to the bottom of the pond.  A build-up of these materials on the pond bottom can create an area where anaerobic bacteria can flourish.  The by-products of anaerobic bacteria are toxic to both fish and plants and can make your pond smell awful.

The delightful sounds of water flowing through a waterfall or playing from a fountain or certainly an enjoyment.  However, they play an essential role in a healthy pond environment.  The water movement should be continuous, meaning your pond pump should run all the time.

How Does my Pond Filtrations System Work?

Many people have the impression that the filtration system on their pond is limited to the physical filtration tanks found near the pond pump. These filters are part of an environmental system that involved your whole pond. You must understand how the pond environment works to understand pond filtration.

Your Pond is an Ecological System

A well-designed pond mimics the environments found in nature.  The environment of streams, lakes, and ponds is part of the water cycle.  The water cycle is a somewhat complicated process, but in a landscape pond, the water cycle utilizes a few critical parts of the complete water cycle.

  • Water Movement – In nature, water evaporates into the air and falls back as rain.  The movement of the water through the evaporation cycle and then through the soil, over rocks, and down the streams into lakes, rivers, and eventually the ocean is the primary way water is filtered in nature.  The filtration system on your pond replicates that natural cycle.
  • The Living Parts – In nature, plants use the water just like the plants in your pond.  They uptake nutrients from the soil that are carried by water.  The same happens in your pond.  The processes providing the nutrients are the same as in the soil and in the water in naturally occurring lakes and streams.
  • What you Can’t See is Important – The heart of a pond filtration system is the bacteria that convert the fish waste, primarily ammonia, into nitrates.  Your pond plants use the nitrates as food, removing them from the water.  Ammonia, nitrites, and nitrates are toxic to fish.  Without these bacteria colonies living in your pond, your fish would soon die, and your plants would starve.
  • Oxygen Every Living Thing Needs it- Without adequate levels of oxygen in the water, your fish will not thrive.  Neither will your plants.  In nature, water movement through the air via evaporation, and over rocks and waterfalls adds oxygen to the water. You pond may have a waterfall, stream bed, or a fountainhead to recreate this natural process.  Some ponds require additional aeration by an air pump connected to air stones on the bottom of the pond.

When these essential parts of the water cycle are put together properly in your pond, the pond environment mimics what happens in nature.  It is the movement of water through this system that keeps it operating at peak efficiency.  In nature, the primary movers of water are natural weather cycles and gravity.  In your pond, the environmental system depends on the pond pump for this movement.

I Have an Air Pump and Air Stones.  Isn’t This Enough If I Want only to Run my Pump During the Day?

Not really.  The air pump and air stones can help keep the oxygen levels in your pond high enough to keep the fish healthy, but air stones and air pumps don’t remove the toxic waste materials from the water.   The bacteria in the filter system do that.  Only running your pump during the day has several detrimental effects on your pond

  • Toxins build up in the water and can reach dangerous levels.  Running your pond pump all the time ensures that toxin levels remain safe
  • The bacteria in your filtration system can be nutrient starved without water flow through the filter.  Nutrient starvation can cause the bacteria colony to decline in the few hours that your water is idle.  Fewer bacteria may not adequately cope with the higher levels of toxins in the water when the pump comes back on.
  • Some systems don’t prevent the water in the filtration system from draining back into the pond.  No backflow preventer can leave your filter system dry.  Your bacteria colony cannot live in a dry environment and will begin to die in minutes without water flow.  No bacteria can leave your pond without filtration when the pump comes back on and no way to mitigate the higher toxin levels in the water.

Keep That Pump Running for the Sake of your Pond and your Pocketbook

In the long run, the cost of running a pond pump is minor when compared to the problems that can arise by only running the pump part-time.  A well-designed pond will do most of the work to keep everything healthy and happy.  To get the full enjoyment of your pond, keep that pump running and let nature do most of the work of maintaining your pond in a healthy condition.


I am always happy to share all my knowledge about how to keep your garden in good condition and make it special.

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