6
4
Filter Media Installation
Step 1.
Leak test the filter. Close all valves
except the flow rate control valve and fill the
filter with water to the maximum water level.
Drain the filter and repair any leaks before
installing the filter media.
Step 2.
Ensure all the filter valves are
closed. Fill the filter 1/3 full with water.
You
can use the water you will be filtering for this
purpose.
Note:
Always add the sand to water
in
order to prevent air locking in the sand
bed of the filter. The sand should be
poured quickly to prevent lensing,
which will reduce the filter’s flow rate.
You will need to add more water as the
sand is being added. When adding
additional water, pour it through the
diffuser to prevent mixing of
previously installed sand layers.
Approximately 15 cm of water above
the sand is desirable.
Step 3.
Add the underdrain gravel to the
level indicated (figure 4-1).
Step 4.
Level the surface of the
underdrain gravel. Referring to Figure 4-
1, add the #3 sand to the level indicated
on the filter body. Repeat this procedure
with the #2 sand and the #1 sand.
Note
: There may be more sand than
required. Do not over fill the sand levels.
However, since the #2 sand tends to settle,
it is acceptable to overfill the #2 sand by a
centimetre above the indicated level.
Underdrain Gravel
Paused Water Level
Maximum Water Level
#3 Sand
#2 Sand
#1 Sand
8cm
5cm
35cm
5cm
Figure 4-1 Filter Media and Filter Water Levels
Step 5.
After all of the media has been installed, use the maintenance drain on the side
of the filter to drain the dirty water off the surface.
