Downs By The Pond
86667 Bailey Hill Road
Eugene, OR 97405
Making the water flow
- Pumps & Plumbing
- Head pressure and friction loss
- Submersible or Inline Pumps
- Plumbing- Flexible Tubing and Rigid Pipe
- Ultraviolet Sterilizers
1.Pumps & Plumbing
The size of the pump you need will be determined by a number of criteria.
Waterfall size, fountain spray and filtration needs all play a part
in selecting a pump. The amount of electricity the pump may use may
also be a consideration Newer energy efficient pumps can pay for
themselves in less than 1 year's time, with the amount of energy
In choosing a pump for waterfall or stream the rule of thumb is 100
gal per hour of pump per 1 width of waterfall. This provides for
a sufficient and attractive flow. Generally 1200 gph (gallons per
hour) is suitable for most small waterfalls, and even most larger
falls do not require over 3000 -4000 gph. For larger displays, it
is sometimes better to use 2 smaller, energy efficient pumps rather
than one large pump. This way, one can service filtration needs,
and the second will provide for increased water flow in falls and
2.Head pressure and friction
Pumps designed for ponds tend to be volume pumps, not pressure pumps.
These pumps are rated, as GPH or GPM (gallon per hour/minute), for
the amount of water they will deliver at a certain height or head.
Head is the rise of the total vertical distance a pump pushes water.
In a pond, this usually means the vertical distance from the pump
to the top of the waterfall. Head or head pressure greatly affects
the amount of water a pump can deliver; increased head= decreased
water. Run, the horizontal distance, also influences pump output,
but to a lesser degree; 10 feet of run is equal to 1 ft. of head.
To determine the head pressure your pump will need to overcome, you
can use this formula.
Depth + 1/10 (distance of run) + height of waterfall = Head
Friction loss occurs within the plumbing system, be it PVC pipe or
flexible tubing, and it too affects the amount of water a pump can
deliver. Friction loss can be minimized by increasing the size of
the pipe or tubing and decreasing the number of bends in the plumbing
3.Submersible or Inline
Submersible pumps are designed to sit in the bottom of the pond,
and they are generally of two types: magnetic operated or mechanical.
Magnetic Drive pumps use an electric coil to turn a magnetic impeller.
They are very energy efficient and therefore inexpensive to operate.
Magnetic pumps are oil-free. This is important as oil-filled pumps
can dump oil into your pond if they overheat or the oil seal deteriorates.
Mechanical pumps are usually less expensive, but they also tend to
use more electricity, and cost you more in the long run. Mechanical
pumps are oil lubricated and as mentioned earlier, can and do leak
oil into your pond which is very messy to clean up.
In-line pumps sit outside of the pond. They often are able to pump
a more substantial volume of water. They can be noisy, so be sure
to choose a quiet model. Their electric usage varies quite a bit,
so you should look at the specs on the particular brand you are considering.
In almost all cases you will want to add a priming pot, since they
are not self-priming.
4.Plumbing- Flexible Tubing
and Rigid Pipe Top
Flex tubing is easy to use, and allows you to follow the shape of
the pond This nearly eliminates the need for elbow fittings and greatly
reduces the friction loss in the plumbing system.
PVC Pipe, though economical, will often require a good number of
elbow fittings and connectors, which are costly and result in greater
friction loss. We primarily use PVC for very long runs where large
diameter pipe is needed. .
Sometimes it is necessary for the tubing to penetrate the liner on
the side or bottom of your pond. Although this should be avoided
if possible, a good watertight seal around the tubing can be achieved
by using Bulkhead fittings or Pipe Boots. Pipe Boots attach using
the same basic process as joining liner, and are pre-adhesived for
Filtration purifies the water, making it safer for the fish, and
more attractive. The entire volume of the pond water should be circulated
through a filter every two hours in small and average pools and for
larger ponds once every three hours. We strongly encourage that anyone
choosing to have fish install a properly sized biological filter
for their pond. Filters are of 3 types, and many are a combination
Mechanical filtration usually relies on a foam pad to collect debris.
It generally has no other benefit.
Chemical filtration uses a chemical means to absorb or neutralize
toxins in the water. The most notable would be carbon, or charcoal
filters. Others detoxify ammonia by the use of chemical additives.
Chemical filters should be removed or by-passed prior to medicating
fish, since they will remove the medicine from the water.
Biological filtration creates an atmosphere in which beneficial bacteria
can colonize. These filters are usually only cleaned once or twice
a year and it is essential to follow the manufacturers recommended
water flow rates for peak efficiency. Using a bacterial product such
as Organic Digester will also add to their efficiency. The bacteria
and enzymes help decompose organic matter and reduce the sludge and
ammonia in the pond. We endorse its use in all ponds with fish. It
also helps in large aerated natural ponds.
Many biological filters have a mechanical component to them as well.
Ultra Violet Sterilizers are not a filter, as portrayed in many garden
articles. UV sterilizers kill the spores of suspended algae in the
water as it passes by a UV lamp. The longer the spores are exposed
to the light, the more efficient it is, and it is important to follow
the manufacturer's recommended water flow rate for the unit.
The resultant dead algae can then be removed by the biological filter.
An ultraviolet sterilizer does not eliminate the need for a biological
filter in a fish pond.
UV lights do not kill string algae. This is a misconception. They
can be used to kill parasites and bacteria in the pond, and therefore
it is recommended to turn off the light for 2-3 days after adding
Organic Digester or any other biological filter starter.