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Top tips for plumbing
your pond.
Pond plumbing
may seem like a complete mystery to many, who quite understandably tend
to think of plumbing in a Koi pond in a similar way to plumbing in a
house. There are however few similarities, not only with the materials
and pumps used, but also in the level of complexity. Pond plumbing
need not, and indeed should not be complex. there are two basic plumbing
systems one for gravity filter installations and one for pump fed.
Pumped
filters.
In pump fed
installations the filter pump is operating in the pond and this is
normally connected to the filter inlet with flexible piping. The UV unit
should be installed between pump and the filter inlet and any heater or
heat exchanger fitted should also be fitted in the same position either
directly before, or after, the UV and before the filter inlet.
Always fit a
suitable slide or ball valve immediately before the filter inlet so that
the pond and filter can be separated and water kept in the filter with
the pump switched off. Input pipe work from pump to filter which is
under pressure should be minimum 1.5 to avoid unnecessary flow losses.
Remember to
keep pipe runs as short as possible with as few bends as possible and
also remember to trim any universal hose tails fitted (often supplied
with pumps and Uvs) to the maximum diameter possible again to avoid
flow restrictions.
Insufficient
pipe diameters and too many restrictions can reduce the rated pump
output by over 50% and put back pressure on the pump leading to
premature failures.
With pumped
installations, the filter must be above the water level in the pond so
that water can be returned to the pond by gravity.
On the return
side of the filter, one would normally use a minimum of 2 pipe work to
return water to the pond. Because the water return operates under
gravity a bigger pipe diameter will be needed to cope with the pump
flow. Also the longer the return pipe work, the larger the diameter the
pipe needs to be, so we would normally recommend a practical minimum
pipe size of 3 for pumped filter returns. It is also normally simpler
to step up a pipe size rather than using multiple smaller pipe returns.
A single 3 pipe has a larger bore area than 2 x 2 pipes and a single
4 pipe has a larger bore area than a two 3 pipes. So in this respect
at least size matters!
Gravity
filters.
With gravity
installations, the water level in the filter is the same as the water
level in the pond, so gravity filters normally reside in purpose made
filter chambers which are excavated at the same time as the pond in
order to simplify construction.
In gravity
installations, the filter input is fed by pressure of gravity, which
forces water through a large (normally 4) pipe buried in the floor of
the pond or fitted low in a side wall and into the filter.
A 4 diameter
pipe is chosen since water flow through it is slow, and solids carried
into the filter arrive intact, this means the filter can cope with these
solids more efficiently, and remove them more easily.
The 4 pipe is
normally connected in the pond to a large sump type bottom drain which
when installed allows water ingress via a small peripheral gap which
prevents fish from entering the pipe work, but allows all the unwanted
solids to pass. The connecting 4 pipe is run horizontally in the ground
or concrete slab under the pond and then exits vertically into the
filter chamber in a suitable position ready to connect to the filter
inlet. Always fit a suitable slide or ball valve immediately before the
filter to separate pond from filter for cleaning and purging purposes.
On the return
side of the filter, water is drawn from the filter by a suitable pump,
which should always be mounted below water level and which is then
connected to a suitable UV (and heater or heat exchanger if fitted), and
then to pipe returns normally fitted into the pond walls. The return
pipe work is normally 1.5 with a gravity installation, as here the
returned water is under pressure. Again never use pipe work less than
1.5 in diameter, and if pipe runs are very long, step up the pipe
diameter to 2 to avoid frictional flow losses in the pipes. Similarly
avoid too many sharp bends in return pipe work, and use swept bends
wherever possible. Always fit a suitable slide or ball valve immediately
after the filter, and before the pump in order to separate pond and
filter to allow for maintenance of pumps and UV and to allow for
cleaning of the filter.
It is always a
good idea to use at least two pond returns, located at opposite corners
of the pond, which will help to maintain a circular flow, even in square
or rectangular ponds, and this helps to "wash" the floor of the pond and
encourages dirt to move to the centre of the pond base where the bottom
drain should be located.
With two (or
more) returns operated from one pump, remember that balancing valves
should be fitted to the shortest return pipe runs so that the flows
through all of the return pipes can be equalised. If these are not
fitted, most of the pumped water returning to the pond will exit the
shortest pipes only as it will follow the path of least resistance.
Top Tips.
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Never put
installed pipe work under stress there is limited pressure in Koi
pond installations, but long unsupported pipe runs full of water and
pipes forced into positions they dont really want to be in are
asking for trouble.
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Always used
solid glued pipe work wherever possible, and NEVER use ANY push fit
components.
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Always fit
pipe runs dry first and mark joints and angles with a felt pen so
that they can be removed and then glued in the correct position.
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Always glue
the shortest pipe runs first you will have more flexibility to
move, remove and refit long pipe runs more easily because the long
pipe will flex and allow more movement.
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Always use
ball valves in any pipe work to control flows.
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Always use
slide valves as waste or stop valve only so that when in use they
are shut. Preferably always mount them in vertical pipe runs.
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Never use
slide valves in a horizontal pipe run so that they are open when in
use, they will fail within months as the shutter grooves fill with
dirt and prevent the shutter from closing properly.
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Always use
a minimum or 1.5 pipe work for pipe runs under pressure and minimum
3 for gravity flow pipe work.
-
Increase
pipe diameters as pipe runs becomes longer.
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Always use
swept bends rather than knuckle bends wherever possible.
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Always use
pressure pipe for buried pipe runs and bed such pipe runs in sharp
sand or pea shingle to allow for movement. Similarly always
use pressure pipe for any pipe runs that are exposed and liable to
be stepped on, kicked or are otherwise vulnerable to damage.
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When
plumbing waste pipe work from filter/vortex drains, always step up
fitted pipe sizes to a minimum of 2 to avoid any possibility of the
pipes becoming clogged with weed and/or leaves and other detritus.
Always use swept bends in waste pipe work.
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Always
install Pumps, Uvs, Heaters etc using demountable single union
connectors so that all components can simply be removed for
maintenance.
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Always
install valves immediately before and after filters (gravity
installations) and near pond returns so that all elements of the
filter system can be removed without water being drained from the
pond or filter.
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In pumped
systems always use reinforced flexible piping from the pump and
NEVER sit the pump on the pond floor always at least 12 above the
base of the pond. In this way should there be a disaster, the pond
can never be completely emptied and the fish will be safe.
-
It is good
practice to use a dedicated pump for the filter flow, and to use
separate pumps for other water features such as waterfalls and
skimmers, which may need to be switched on and off, or may operate
with variable water flows.
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