1.
ESSENTIALS FOR A HEALTHY POOL OR SPA
Recommend daily levels for swimming pools and spas as determined by a testing kit
Swimming Pools
Spas
Free Available Chlorine
1.0
–
3.0 ppm
3.0
–
5.0 ppm
pH
7.2
–
7.8
7.2
–
7.8
Total Alkalinity
100
–
120 ppm
100
–
120 ppm
Calcium Hardness
200
–
300 ppm
150
–
200 ppm
Check the expiry date on the test kit, as test results may be inaccurate if used after that date
There are three fundamental requirements in maintaining a swimming pool or spa:
a) FILTRATION
b) CHLORINATION
c) pH
A pool or spa should be looked at daily to check that the water is clean and clear
and the finest details of the pool or spa walls can be seen at the deepest part. This
will indicate whether the pool or spa has had enough filtration and chlorination for
the load conditions that were applicable the day before. Any other condition
requires testing and rectification before entering the water.
a) FILTRATION
It is first necessary to pass water through a filter to remove debris. A standard sized
pool
pump
with
normal
filter
pressures
will
pump
about
10,000 litres
(2,642
gal)
an
hour, so an average 60,000 litre (15,850 gal) pool then requires six to ten hours of
filtration a day in summer conditions. This will turn over the equivalent of 1 1/2 times
the total volume of water. However, only about 65% of the actual water and debris
will have passed through the filter.
Generally, at dawn and at dusk, wind dies down and these are the best times to
commence filtration. Leaves and floating debris will be swept to the skimmer box
without restriction if the pool is well designed.
For spas, the water typically turns over several times per hour with all of the water going
t
hr
ough
a
f
i
l
t
r
a
t
i
on
s
ys
t
e
m.
(
r
e
f
e
r
t
o
s
pa
owne
r
’
s
ma
nua
l
f
or
de
t
a
i
l
s
.
)
Longer filtration cycles can reduce the chlorine requirement and conversely, more chlorine
can reduce the filtration requirement. The level of chlorine in the pool or spa is a function of
what is going on in the pool or the spa.
b) CHLORINATION
The WATERMAID chlorinator takes care of the chlorination aspect of these requirements.
As mild saline water flows through the WATERMAID Cell it is converted, by electrolysis,
into chlorine as sodium hypochlorite.
After filtration, chlorine is required to react with any remaining debris (both visible and
non-visible), remove stains by oxidation and to sanitize the water of harmful bacteria. A
chlorine residual (or reserve) is required for any imminent bather load.
