Article 2 - How to Choose a
Pond PumpPond Pumps
Pond 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 planning to create water effects in your pond. Even if you are not planning
to have fountains, or waterfalls, pond pumps are essential for oxygenating
your pond.
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. So, if you have
a pond with 2,000 gallons of water then your pump needs to at least
circulate 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. Generally a waterfall
requires 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.
So, which type of pond pump is right for you? That depends upon your
pond's design and purpose. Submersible pumps are best suited to small
to medium sized ponds with roughly 200 - 800 gallons of water. 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. 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
an external pond pump. On the downside, they can cost more to operate
and usually don't last as long as external pumps (having shorter
manufacturer warranties.) 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!
Many variables are taken into account
when 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 the life span
of a pump.
Submersible pump power supplies come in 110 240 volts, 12 or
24 volts, or solar powered. Solar submersible pumps are becoming more
popular - but you need lots of sun for effectiveness and, of course,
they won't run at night when your water needs the most oxygenation.
Your pond may be too large for a submersible pump. If so, then an external
pond pump is your best choice. External pond pumps are best suited to
medium to larger sized ponds with 1000 gallons of water or more. These
are often the best choice because they are typically more energy efficient
and can handle larger water flows. They are also designed to work well
with most biological filters, which can cause significant backpressure
on the pump. These pumps usually come with a priming pot and leaf strainer
which is easily accessible without having to get your hands wet. Flow
rates typically range from 1800 GPH to as high as 7000 GPH, or higher 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.
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 submersible cousin. Most submersible pumps carry a 1 year
warranty, and tend to last up to 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
on an external pump can be replaced rather
easily. As I mentioned before, when something goes awry with a submersible
pump, it's next home is the trash can!
For more information about pond pumps, please visit us at www.macarthurwatergardens.com
Until then - Happy Pondkeeping!
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