| How to Choose a Pond Pump
There are many factors to consider when choosing a
pond pump. Some of those factors include:
- If you want a submersible pond pump or a
non-submersible pump. A non-submersible pump can be called an
external pump or a centrifugal pump.
- What type of voltage of pump you want.
For most backyard pond applications, a 120 volt is typical.
For larger pond pumps and waterfall pumps, a 220 volt may be what
you need.
- What type of pressure you need. This is
referred to as GPH (gallons per hour) or GPM (gallons per minute).
- What size of plumbing you may already have in
place.
Benefits to having a submersible pond pump is that
it can be concealed and out of view by placing it in the pond. It
also can eliminate any noise by having it submersed in the pond water.
A 'downfall' of having a submersible pond pump is that if you want to
unclog it or remove it for the winter, you have to get in the pond in
order to remove it. A neat idea, though, may be to tie some black
nylon rope on it's handle (if applicable and not too heavy) and conceal
the nylon rope (which will float). When it's time to remove the
pump, you may be able to grab on to the nylon rope and pull it up.
Benefits to having a centrifugal or out-of-pond
pump is that it's easier to maintain by eliminating having to get into
the pond to access it. They can be a bit noisy though, depending
on the size, which may be muffled or eliminated by placing a fake rock
cover with air vents over it. Centrifugal pumps are designed to
push water, not pull it, so they should be located at water level near
the pond's edge and then push the water up to a waterfall or nearby
water feature.
Centrifugal pumps or submersible pond pumps can
also be used as irrigation pumps. Many people who have a pond on
their property set up their pump by pumping the water from the pond and
using it for irrigation purposes. Either a centrifugal pump or
submersible pump can be used for irrigation.
Determining the
Size of Pond Pump You Need
After you've determined whether you want a
submersible or centrifugal pump and the voltage you have available, you
will then need to decide what size of pump your water feature needs.
To calculate the size, there's a little math involved and a few
measurements you will need to get.
In order to calculate the size of pump you need
just for a specific water feature (and NOT to provide overall pond
circulation), then here's some steps will need to take:
1. Measure the width of your water feature,
such as a waterfall. The width of the weir is what you need and
the weir is the top of the waterfall area where the water first drops or
'falls'. Measure this in inches. Write the number of inches
down. As an example, say your waterfall is going to be 24" wide.
2. Measure the horizontal distance from
where the pond pump would be located to the waterfall. As an
example, say your waterfall is going to be 25 horizontal feet away from
your pump. You pond that you're going to make is going to be 15'
long and you'll put the pump at the opposite end of the pond as the
waterfall which will be 10' away from the pond's edge. Add up 15'
+ 10' and you get a total of 25 horizontal feet.
3. Now, measure the height the waterfall
will be from the surface of the pond water. Note, I said surface
of the water. For our example, the height of the waterfall will be
3' high - or 3' higher than the water's surface.
4. Now, here's where we plug in our numbers
and do a little math. Don't worry, it's pretty easy. For
every 10' horizontal distance the pump is going to push water, you add
1' LIFT. I know you haven't heard of 'lift' yet, but just write it
down for right now. In this case, our pump was going to be located
25 horizontal feet away from the waterfall. Divide 25 feet by 10
and you get 2.5' of LIFT. Write that number down.
5. For every 1' of vertical height the pump
is going to pump water, you add 1' lift. In our case, the pump was
going to pump 3' high. So, 3' divided by 1' and we get 3.
This number is also part of our 'lift'.
6. Add the horizontal lift (which was 2.5')
and our vertical lift (3') and you get 5.5' of lift. Write this
down and circle it. Put it in bold. It's very important.
7. Now, in regards to the actual waterfall
itself.... You want to create a waterfall that is 24" wide, right?
(Wink, wink! Of course you do! :o) Or at least, that's our
example any way!) Here's our little math for this part of
the equation. It's even easier than the lifts, so don't
worry! Here it is: For every inch wide the
waterfall weir is, you multiply this number by 100 GPH. So,
since our waterfall weir is going to be 24" wide, we multiply 24" x 100
GPH and we get 2400 GPH. Write this number down. Circle it.
Put it in bold. It's part of what you need.
8. Now, we'll put it altogether! You
need a pump that will pump 2400 GPH at a 5.5' lift. Let me
tell you this... This is NOT a 2400 GPH pump! This is a pump
that will pump 2400 GPH at a 5.5' LIFT! Let me explain...
Manufacturers of pumps will include performance
charts for their pumps. This performance chart indicates how many
GPH (gallons per hour) that particular pump will push water at a certain
'lift'. Typically, the LABEL ON THE PUMP INDICATES A 0' OR 1'
LIFT. You will have to read the performance chart for your
specific pump to make sure it can pump 2400 GPH at a 5.5' lift.
This size of pump may be labeled as a 2850 GPH or some other number
because the pump 'may' push 2850 GPH at 0' or 1' lift but by the time it
pushes the water at a 5.5' lift, the amount of water pressure is less...
The lower pressure available at 5.5' lift may be just what you need - or
it may be too much or too little. So, you will have to check the
performance chart for each pump and DO NOT refer to the label of the
pump as this is typically labeled at a 0' or 1' lift - NOT the lift you
need!
I tell you all of this because it's VERY important
no matter if you're looking for a submersible pump, centrifugal pump or
irrigation pump. There is a little math you need to do in order to
determine the right size of pump for your application. What
happens if you don't do the math? Your pump is too small for your
pond... or your pump may be too larger for your filter or waterfall and
it pushes water everywhere. You get the picture...
For larger pumps required for large water
features, the performance chart can show a dramatic change for just a
few feet so be sure to do your math and measure everything, too.
Also, in regards to large pond pumps including
centrifugal or submersible pumps, many people think that you need a
certain HP or horsepower to provide the flow you want. This is NOT
true! Manufacturers have continued to make their pumps more energy
efficient and many pumps on the market today require less energy they
did years ago while providing the same or more pressure. So,
don't go by horsepower. Some are also designed to provide a whole
lot of pressure but not for a long distance while other pumps are
designed to go a long distance but not with a lot of volume. All
the pumps are different. Bottom line: Check the performance
charts for any size of pump. Pumps are non-returnable too, so you
want to make sure you've calculated the size you need correctly.
Well, I hope this helps. We have a huge
variety of pond pumps including submersible pumps, waterfall pumps,
centrifugal pumps, irrigation pumps, etc. If you need help in
determining what size of pond pump or centrifugal pump you need, don't
hesitate to ask. Simply email us with your measurements and we'll
be happy to help!
Once you have chose the right size of pump you
want, then you'll be able to determine what size of tubing you will need
to do your plumbing as the intake and discharge size of the pump is the
size of tubing you will need for your application.
For those requiring more specific information
including pipe friction loss, industrial pumps, etc., please contact us
with information for your application.
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