Pump Principles...For Your Koi Pond
Reprinted with permission of the author
Rod Talley, Performance Pro Mfg.
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| There are many good ways to plumb a pond. These hints are
offered, first, as tried and true - but not necessarily the only
methods. Secondarily, I hope to give the reader some sense of
the principles behind lowest cost, most reliable pond recirculation
and water service. Several thoughts should be kept in mind as
we begin our subject: |
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| First, a koi pond should not
be plumbed like a swimming pool. A swimming pool
uses a low volume, high pressure water system: Small pipes. Big
pumps. Your pond should be low
pressure, high volume, use pipe with an inside
diameter of at least 2" going to the pump, and 1 1/2"
to 2" or even greater diameter leaving the pump. |
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| Low pressure, high volume
is better achieved with a smaller
pump than with the ones normally associated with
swimming pools and spas. Realize, too, that the
pump should run 24 hours a day. For most applications,
if your pump requirement is greater than one-quarter horsepower,
you probably have a plumbing or filter problem which should be
rectified. In addition, the right
pump, properly plumbed, can save 50 percent or more per month
in electricity over the wrong one: |
- Locate the pump as close to the source as possible.
It is best to have your main run of pipe on the discharge side
of the pump.
Install the pump outside the pond,
and below the level of the surface of the pond
to create flooded suction. This will help to ensure a proper
supply of water to the pump. Remember, a pump can't pump out
water if there isn't any available. Even if your supply line
comes up and over the top of the pond wall, it will still offer
a flooded suction if it has no breaks to atmosphere before it
goes back down below the surface level.
- If it is not possible to provide a flooded suction installation
then: position the pump as low as possible, and as near the
source as possible.
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Install a priming pot on the inlet of the pump.
Install a foot valve, or a check valve in the inlet line below
the water level.
Always prime the entire inlet line, priming pot, and pump
before turning it on.
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- Always have your inlet pipe diameter equal to or
larger than the discharge line.
- Use large enough pipe to minimize friction loss.
You receive no benefit from fighting friction. It is much better
to spend a little more money on the pipe initially, than to continually
spend more money on electricity to produce pressure to fight
friction. We suggest keeping your friction losses to less than
10 feet per 100 feet of pipe. It costs money to create pressure.
The longer the run of pipe you use, the more critical this is.
To determine your losses to friction, determine your flow rate
and consult a friction loss chart. The inlet and discharge port
sizes of the pump do not dictate the proper pipe diameter to
use. Normally a minimum of two inch line on the inlet side of
the pump and one and a half inch line on its discharge side is
suggested for flow rates of up to 50 gallons/minute.
- Use a filtration system that does not require a lot
of pressure. It costs money to create pressure. Biological
filters work best anyway.
- Never allow a horizontal centrifugal pump and motor
unit to become submerged. If this ever accidentally
occurs, shut the unit down, disconnect it, and have a reputable
service shop examine the motor.
- Never run a pump dry. This will damage the
seal and impeller. They are designed to pump fluid, not air.
Ensure the pump is full of water before you turn it on, and that
it doesn't outpump the supply.
- Shelter the pump and motor unit. They will
last much longer when protected from rain and rust. The covering
should still allow the unit to have suitable air circulation
for proper cooling.
- If more flow than a single unit can produce is required,
use two or more units in parallel. This also offers the benefits
of being able to vary the flow rates, ensure partial flow if
one unit needs servicing, and can often save a substantial amount
of electricity compared to using one very large pump.
- Choose a pump that can give you the required flows
at the lowest possible amp draw, and its effect on your
monthly utility bill can be significant.
- If you want to reduce the flow rate of the pump, you can
partially close a valve on the discharge side of the pump only.
- Check to be sure the motor's electrical connections
are set up to match the supply voltage.
- Install shutoff valves before and after the pump,
so you can easily remove it from the line without having to drain
your system.
- Use teflon paste (not tape) for sealing
threaded joints.
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