Cleaning Pool Water
Pollution in pool water comes either from the environment
or is carried into the water by the swimmers. Environmental
pollution includes dust, leaves, chemical wastes, pollen,
spores, bacteria and so on, that are blown into the water by
the wind. Swimmers carry other pollutants into the water:
sweat, suntan oils, urine, bacteria, viruses, etc.
Every swimming pool has a circulation pump and filter.
The filters most common these days are sand filters, and are
much easier to maintain than the earlier diatomaceous
filters of a few years back. The pool pump ensures that the
swimming pool water moves through the filter every day, thus
removing unwanted pollutants and disinfected organic
materials as quickly as possible.
Other common pool filters include DE (diatomaceous earth)
filters, which are able to filter out finer particles of
dirt, though they require more maintenance. Cartridge
filters are also quite widespread and are quite simple to
maintain. Nowadays a filter sand substitute containing zeolite
is gaining in popularity. The zeolite (specifically the
clinoptilolite mineral) is able to filter particles as
finely as DE filters in addition to having a capacity to
absorb ammonia and its complexes (reducing combined chlorine
and offensive chlorine odours), while not requiring any
extra maintenance.
Generally, the swimming pool pump
should run for at least 6 - 8 hours each day. There
is usually a timer which cycles the pool pump on and off to
ensure this constant filtration. The circulation of pool
water will remove floating or suspended particles of dirt
from the water, but has no effect on the substances which
have settled to the bottom of the swimming pool or
"stuck" to the walls.
Depending on the environmental conditions and swimmer
load, the swimming pool needs regular
brushing and vacuuming, generally about once a week
in the swimming season for home pools. With the circulation
pump turned off, the walls and floor of the pool are swept
with a stiff brush. When the "dust" from the
brushing settles, it is vacuumed off the floor of the
swimming pool. The pool must also be vacuumed after treating
with a flocculant. Nowadays, there is a variety of automatic
swimming pool cleaners, which suck the dirt off the walls
and floor of the swimming pool whenever the pool pump is
running. These are really great for pool owners who never
seem to have the time for swimming pool chores.
Now that the vacuuming is done, it
is time to backwash the filter.
Sand filters trap dust and dirt, as the name implies, in a
bed of sand. When the filter has accumulated a large amount
of dirt, the water cannot pass freely through the sand and
the filter loses efficiency as the pressure increases.
Backwashing sends water backwards through the filter and
flushes the trapped dirt out. After backwashing, you will
notice an increase in return pressure to the pool, and if
you have a pressure guage, you should notice an increase of
at least 0,5 bar.
With the pool pump off, turn the filter setting to
"backwash". Remove the leaf basket from the weir,
clean and replace it. Turn on the pump and let it run until
the water coming out of the waste pipe is clear. This
generally needs a few minutes. Turn off the pump and set the
filter to rinse; this cleans out the pipes and prevents any
dirt from returning to the pool. It also settles the sand in
the filter which has been stirred up by the backwashing. Run
the pump for about a minute and then turn it off. Set the
filter to "closed". Open the leaf trap near the
pump, remove the basket and clean out all the leaves, twigs
and rubbish it may have collected. Replace the basket, set
the filter to "filter" and turn your pump back to
its automatic (timer) operating position.
Great! The swimming pool looks clean and the filter has
been rejuvenated. Now it's time to test the pool water and
adjust the pH and chlorine levels.
If your swimming pool needs topping up, now is the ideal
time to put the hose in the pool. It is very healthy for the
swimming pool water to be replaced bit by bit, to prevent it
becoming stale and creating chemical problems or pool water
problems. A routine of 5-minute backwashing followed by a
1-minute rinse every week will ensure that you replace about
5% of the swimming pool water each month. This means a
complete changeover of swimming pool water approximately
every 2 years.
REMEMBER too, that the useful
lifespan of the sand in your filter is 3-5 years. If you
neglect to change the sand, your filter will not be able to
remove the finer particles of dirt and your swimming pool
can never be completely clean. Have the pool filter opened
for inspection at least every 2 years to avoid filtration
problems.
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