How do I work out the flow I need for my pond pump?
Knowing pond pump flow is critical for good pond pump choice
– save money at the same time. Beware of maximum flow specifications on
box
Be aware that pond pump flow is the amount of water required to give
you the waterfall effect you desire in garden ponds and/or provide the
bacteria in your pond bio filter with enough well oxygenated water to
allow them to do their job of purifying pond water around the clock... Correct
specification of pond pump flow and pump head is very important. Too
little flow and your waterfall will be a disappointment. Too large a
pond pump with too much water flow down a waterfall will waste your money and the noise may well annoy
you and your neighbors too. You must be able to determine the correct pump flow for your system in
order to specify the correct pond pump. This is a MUST. By the way ribbed hose
pipe is by far the best pipe to use on a garden pond since it
does not restrict pump flow when bent to form curves or bends often
required in a pond set-up. How to measure water flow for an intended
waterfall using a garden hose pipe
There are 2 basic ways and both involve a bit of calculation. One
technique uses a hose pipe attached to the garden tap. here's the
procedure for this method of water flow calculation ... If you would
like to test how much water looks best for your waterfall do the
following ...
-
Place a hosepipe into the waterfall
inlet
-
Adjust the flow until you are happy
with the effect
-
Without closing the hose fill a known
volume container from the hose pipe
-
Calculate the flow rate by dividing
the volume of the container by the time taken to fill it. This
week's free calculator could come in useful here.
-
This calculator would also allow you
to weigh the container as an alternative to knowing its volume. For
water use the following:
-
1 US gallon weighs 8.83 lbs
-
1 Imperial gallon weighs 10 lbs
-
1 litre weighs 2.2 lbs
-
If one hose does not deliver
sufficient water then use 2 hose pipes.
How to calculate waterfall pump flow rate required using width of
the waterfall overflow (lip)
A typical waterfall cascades over at least one edge. I will refer to
this edge as the lip of the waterfall ... it is how wide this lip is
that determines the flow required for a soothing waterfall sound. Of
course you can have more or less water flowing down the waterfall but
this is a good starting point to decide how much water you want to flow
from your pond pump. If your waterfall does not have a simple or
single edge or lip then you must approximate. For example lets say there
are 3 different overflow points and each one is 3 inches wide. Then use
a total width of 3 x 3 inches = 9 inches. For each inch of lip width
allow for the following pond pump flow rates per hour ...
63 US gallons per hour for every inch (2.5 cm) 55 Imperial (UK)
gallons per hour for every inch (2.5 cm) 250 litres per hour for every
inch (2.5 cm) Tip to improve appearance of waterfall without buying a
larger pond pump
An under-powered waterfall is always disappointing. To make your
waterfall look and sound better without buying a new pond waterfall pump
do the following ... Place some nice looking river pebbles at various
points close to the overflow point(s). This has the effect of reducing
the width of the lip over which the water from the pond pump must flow.
How to decide upon pond pump flow required if you do not have a
waterfall
If you have a fish pond with no waterfall the pond pump flow is
determined mainly by the pond bio filter requirements for oxygenated
pond water. You will remember that every fish pond needs a biofilter and
that it is bacteria inside the bio filter that keep the pond water clean
and health for the fish. To simplify the pond pump flow for this
situation it is good enough to use the pond volume as the starting
point ... yes this means you need to have a good idea of your pond's
volume. If you click this link it will show you how to
calculate the pond volume. Most pond
filter systems are satisfied by using a pond pump that will pump the
volume of the pond through the filter between 8 and 12 times per day or
put another way by using a pond pump that will pump the pond volume
between every 2 or 3 hours. So if your pond has a volume of 900
gallons then a pump that will deliver between 300 and 450 gallons per
hour is good enough. Now you know how to calculate pond pump flow and
pond pump head lets show you how to use a pump curve ... click here
how to read a pond pump curve
In addition to pump head and to fully specify a pond pump you need to
know exactly what pump flow is needed for your garden pond.
When you see maximum pump flow referred to on a pump box do not use this
for any practical purpose.
The information on many pond pump boxes must be treated with some
caution. Good pond pumps suppliers clearly state volume flow at
different heads. If you only see maximum pump flow stated on the box BE
CAREFUL since the pump is only able to pump this amount with no pipe
attached to it. Maximum flow is an impractical indication of true
usefulness of a pump.
Think of pond pumps flow as the amount of water to be pumped around your
pond system to give you a waterfall effect you will be happy with.
In addition pump flow must also satisfy the needs of your biofiltration
system.
To save lots of money think of running two separate pond pumps in any
pond with a waterfall – big or small pond, it does not matter. This
subject is covered extensively in my book and this advice alone covers
the cost of the book many times over.
In order to fully specify a pond pump you need to know in addition to
pump flow exactly what pump head is needed for your garden pond.
Choose low cost reliable supplier on-line
I suggest you look a both suppliers and compare prices and shipping
costs ... take note that both suppliers offer specials at times and
these often appear in right hand border of this website.
These suppliers do sell other makes of pumps also of high quality and
performance which you might want to investigate and you can search the
websites for the model you want ...
Florida based
supplier specializing in very wide range of garden fish pond equipment
including pond pumps filters and UV lights ... just click the link
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