Submersible Water Pump Problem Solving Guide For Fish Ponders
WHAT DOES MAXIMUM HEAD MEAN?
This bit of information means the head or height difference between the
water surface and the waterfall the flow from the pump will be 0 litres per hour
- i.e. there is zero flow.
This information about maximum head should be ignored or only used to compare one
pump to another. This information has mislead many people into buying the
incorrect pump. It is important to know how much water the pump can handle at
different practical heads or height differences between the water surface and
the waterfall inlet for example.
IS IT BEST TO BUY A CHEAP PUMP OR AN EFFICIENT PUMP SPECIALLY MADE FOR POND USE?
The majority of retailers who sell pumps will never mention the advantages of
low power consumption pumps yet this is a very important part of a purchasing
decision. We would go as far as to say that the concerns over running costs could
outweigh those concerning the cost price.
The best thing to suggest is check out this very important pump comparison page
and you'll see how you can save a lot of money by understanding pumps for your
HOW DO I KNOW HOW MUCH WATER MY PUMP MUST HANDLE?
As a basic rule a pump should pump the total volume of the pond every 2
hours. In this way the contents of the pond are circulated 12 times a day. At
this flow rate there is a good balance between the needs of plants, fish and the biofilter in a pond system. You may want to pump more than this if you want an
impressive waterfall effect.
A pond of volume 5,000 litres would be happy having a flow rate between 2,000
and 4,000 litres per hour. A pond of volume 2,000 litres would be happy having a
pump flow rate between 700 and 1,600 litres per hour. The important point is to
get the flow rate somewhere between one third and about two thirds of the pond
volume for a good balance. What is more important is that if your pond is say
1,000 litres you certainly do not need a pump that can do 5,000 litres per hour
HOW CAN I TELL IF A PUMP IS SUITABLE FOR USE IN A POND?
Pond pumps are designed to operate in harsh outdoor environments. In practice
this means the water in which they reside becomes polluted. Foreign objects find
their way into the pump moving parts and can do damage if the pump is not
designed to withstand these rigours
It is illegal to sell an outdoor pump unless there is at least 10 metres of 3
core cable attached to it. The box and if not the box the label on the pump
itself will indicate indoor or outdoor ( a small sign showing picture of house
with arrow pointing into the house indicates for indoor use only). The pump will
have 2 or 3 year guarantee period. If any of these are missing do not buy the
pump for use in a pond.
WHY IS THE GUARANTEE IMPORTANT?
A 2 or more years guarantee tells the customer especially when it comes to pond
pumps that the design is good, the performance good, and that the manufacturer
stands behind their products.
A pond is a very harsh environment in which a pump has to run 24 hours a day 365
days a year. When you see a 2 or more years guarantee on a pump you can buy with
total confidence. Beware of Sump pumps. These pumps are powerful and large -
they stand upright and are therefore easily recognised. Sump pumps are designed to
run for a certain amount of hours and since they are primarily designed for
intermittent running their life span can be considerably shortened when run
continuously in a pond.
HOW TO SELECT THE CORRECT PUMP
Selecting the correct pump is critically important. Apart from doing the job you
want it will last you a long time and running costs will be very low. If you
want a waterfall and no fountain choose a pump which does not need a sponge on
the suction side of the pump. This saves a lot of maintenance. Do ask us for
advice if you are not sure.
You can tell a pond
pump very easily. It will have 10 metres of 3 core cable and the box will tend
to be larger. There will be a guarantee of at least 2 years - DO NOT buy 1 yr.
guarantee pumps for ponds. They do not last. You need to specify how much water
in litres per hour you want to pump and to what height this quantity must be
WHAT DO PEOPLE MEAN WHEN THEY TALK ABOUT THE HEAD OF A PUMP?
This is a fancy word for what pressure can the pump develop. In other words how
high can it pump.
Head is the height difference between the water surface in the pond and the
outlet point of the pipe attached to the pump. If the outlet pipe from a pump
was lifted 50 cm above the pond surface then a certain amount of water would
flow out of the pipe. If the pipe was then lifted to 1 metre above the surface
of the pond then a reduction in flow would be seen. What we now see is that the
higher the head for the pump then the lower is the amount of water pumped.
WHAT DOES MAXIMUM FLOW MEAN?
Maximum flow is the absolute maximum water the pump can handle. However it is
only able to pump this amount with no pipe attached to it. It is an impractical
indication of pump usefulness
Maximum pump flow information should be ignored or used for comparison only. It
has mislead many people into buying the incorrect pump. It is important to know
how much water the pump can handle at different pumping heights.
Pumps and Fountains
I MUST HAVE A FOUNTAIN IN MY POND
If you need to run a fountain in your pond it normally makes good sense to
select a pump that comes with these fittings.
Most Hozelock pond pumps are supplied complete with fountain attachments. If you
buy the fountain attachment later it may be expensive. On the other hand there
are some very impressive fountains which might appeal to you. If you want to run
both a waterfall and a fountain make sure your pump is powerful enough. You must
run the pump with the sponge in the suction to prevent the holes in the fountain
blocking with debris. The bell fountain is a very popular design.
Pumps and Waterfalls
DO I NEED A WATERFALL?
It is a good idea to have a waterfall for the following reasons: to hear running
water, to add character to your pond feature, to add oxygen to the water for the
benefit of the fish and the biofilter and to use the soil that came out of the
ground when you installed the pond.
A waterfall with a wide lip will need more water than one with a narrow lip to
create a good effect. In my experience the fibre glass rock-like waterfalls are
perfect for most garden ponds and are well designed to handle the appropriate
water flow for the size of the waterfall itself. Very few garden ponds benefit
from a waterfall as high as 1 metre and even this is probably too high unless a
cascade effect rather than a fall effect is required. An ideal height for a
waterfall is between 40 cm and 60 m.