Freshwater Pond Fish Pump Calculation

by Brett Fogle

Freshwater Pond fish pumps are the very heart of any fish pond. All water gardens can be enhanced by the addition of water fountains, waterfalls, and other moving-water features. The pond pump is your best friend if you’re planing to create water effects in your pond. Even if you are not planning to build waterfalls or fountains, pond pumps are important for oxygenating your pond. In the other word it’s also seems as an aerator.

When choosing a pond pump, keep the following requirements in mind. The first thing is to determine your required flow rate. Your minimum flow rate should be at least half of your pond volume. At least you should have a pump which powered to circulate half of your pond water volume per hour. For example, if your pond water volume is 2,000 gallons, then your pump needs to circulate at least 1,000 gallons per hour (gph). This is a minimum.

You might find that 1,000 gph is not enough if you will be including. For example, a waterfall that is more than 10 inches wide. Commonly a waterfall needs 100 – 150 gph per inch of width of the weir (the portion that the water spills over). This can vary depending up on how smooth or rough the weir is. You will also need to be sure that the pump moves enough water to satisfy the requirements of your filter and ultraviolet sterilizer.

Freshwater Pond Fish

So, which type of pond pump is right for you? That depends upon your pond’s design and purpose. Submersible pumps are best choice for small to medium sized ponds with 200 – 800 gallons of water volume range. These types connect easily to most of the submersible filters built for small to medium sized ponds. Flow rates usually range between 250 GPH and 4,100 GPH. for a larger waterfall pump.

Submersible pumps operate inside the pond. They are generally low cost to buy and operate. Many models of submersible pumps are available, and they are a good choice for flow rates around 1,000 gph or less. Submersible pumps are usually less expensive and easier to install than and external pond pump. On the downside, they can cost more to operate and usually don’t last as long as external pumps. The motors of most submersible pumps are totally encased in a resin so that they are safe to use underwater. Most submersible pumps cannot be repaired for safety reasons. So once it wears out, it’s time to get a new one.

There are a lot of variables in determining how long a good submersible pump will last. Issues such as how dirty the water is, how often the pump is cleaned, and if it is operated nonstop all will influence a pumps life span. Submersible pump power supplies come in 110 – 240 volts, 12 or 24 volts, or solar powered. Solar submersible pumps are becoming more popular, indeed you need lots of sun for effectiveness and, of course, they won’t run at night when your water needs the most oxygenation.

If your freshwater fish pond was too large for a submersible pump. Then an external pond pump is best choice for your pond. External pond pumps are best suited to medium to larger sized ponds with 1000 gallons of water or more. Beside they could handle larger water flows, also they are typically more energy efficient. They are also designed to work well with most biological filters, which can cause significant back pressure on the pump. These pumps commonly come with a priming pot and leaf strainer which is easily accessible without worried about wet hands instead keep your hands dry.

Flow rates range from 1800 GPH to as high as 7000 GPH for a larger pump. Generally, the ideal external pump will circulate the total volume of the pond at least once per hour. For example, if you pond is 2000 gallons, you would want to go with at least a 2000 GPH pump.

Pick the most fit pump for your pond

There are several advantages to a submersible pond pump over a submerged pump. They are more energy efficient, resulting in lower annual operating costs and they tend to last longer. On average, submersible pumps tend to wear out after about 1 year because they spend their life sitting smack in the middle of pond sludge which eventually damages the pump’s impeller.

Overall, an external pump has a longer mean time between failure (MTBF) than it’s submergible cousin. Most submersible pumps carry a 1 year warranty, and tend to last around 18 months. Do the match and you’ll see that a longer-lasting external pump is almost always the best bargain. Finally, unlike a submersible pump, most parts can be replaced rather easily. As I mentioned before, when something goes awry with a submersible pump, its next home is the trash can.

For more information about freshwater pond fish pumps, please visit us at


Leave a Reply

Your email address will not be published. Required fields are marked *