The
base for the filters |
Most
books deal with putting in the filters after they have complete
building the pond, but in fact it is important to have the
filters on site before you start any digging.
The water level in the first chamber will govern the final water
level in the pond so it is important to put the Vortex chamber,
or whatever you are using in place at the early stages.
|
TIP. The
vortex chambers vary a great deal in size from one manufacturer
to another, and do not always conform to the sketch or diagram
they may have given you. Nearly everyone I have seen building
ponds seem to have dug too deep for the filter base, and
then have had to get in rubble to build back up to the correct
level.
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|
The
two photos above show the base for the filters. The base
is six inches thick and steel reinforcing mesh has been used
to strengthen it. The mesh is raised up so that it will be
in about the middle of the concrete.
The filters will be situated
behind the hedge so that they cannot be seen from the pond
area. Fortunately the ground level slopes away in this area
so no digging was necessary for the filter base which would
normally be required with an in-ground pond.
|
TIP. If
the ground had been level then the base for the filter system
would have been say three feet below ground level. (The water
level in the filter must be the same in both filter and pond
as the filter is fed by gravity). In this case the base would
need to be made slightly larger, and then walls of 18 x 9
x 4ins concrete blocks built up to make a wall 4 inches thick.
The space behind the walls are then backfilled.It is not
necessary to render the blocks. |
 |
The filters that
Mark has decided to use are three Nitritech units from Koi
Southwest, Bristol, and two of the three units can be seen
here. The children have decided that at least one of them required
extra decoration. |
| The next
step is the pipework for the bottom
drains. |
|
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