TOTAL ALKALINITY
This is a measure of the alkaline nature
of the water, which at the pH encountered in swimming pools is
predominantly bicarbonate. As with most things to do with pool
chemistry there is a compromise situation between corrosion, scaling,
sanitiser efficiency and ease of maintaining pH. The range to
aim for is 80 to 150 p.p.m.
To raise total alkalinity add Alkalinity
builder (Sodium Bicarbonate).
To lower total alkalinity add pH Minus
BROMINE TABLETS
A Bromine tablet weighs about 18 gms. As
these slowly dissolve the free bromine level will rise as indicated
by this calculator In spa baths and small domestic pools,
maintain a free bromine level of 2 to 3 p.p.m. In larger more
heavily used pools, or commercial pools where the bather load
is higher, aim for 4 to 6 p.p.m.
SHOCK CHLORINE
Calcium Hypochlorite is usually preferred for indoor pools where
the effects of sunlight are less. When used outdoors, a separate
stabiliser must be added to slow chlorine loss in sunlight. For
sanitising, the typical free chlorine level would be 2 to 3 p.p.m. for
domestic pools, 3 to 5 p.p.m for heavier used pools. 10 p.p.m
or more is the shock treatment level, following which, the level
should be allowed to drop below 5 p.p.m before bathers enter the
water.
TIP - Add shock chlorine at night so that it can work in
the dark to maintain its strength for longer.
TIP - In soft water, Calcium Hypochlorite also builds the
Calcium content of the water.
NOTE - At free chlorine levels above 10 p.p.m, the water
sample colour using Phenol Red test tablets may be bleached. This
could give the impression there is no chlorine when there is quite
a lot.
CHLORINE GRANULES
This provides an easy way to add chlorine
to outdoor domestic pools where the stabiliser resists the chlorine
loss caused by sunlight. The typical free chlorine level would
be 2 to 3 p.p.m. it is not ideally suitable for "shocking"
or "Superchlorination" For this purpose we recommend Shock Chlorine.
CHLORINE TABLETS
These are supplied in slow dissolving tablets of 200gm. It provides a very
easy way to add chlorine to outdoor domestic pools where the stabiliser
resists the chlorine loss caused by sunlight. The typical free
chlorine level would be 2 to 3 p.p.m. Not suitable for "shocking"
or "Superchlorination". For this purpose we recommend Shock Chlorine. This calculator
shows the grammes of tablet used for each p.p.m free chlorine.
HARDNESS INCREASE
The principal water hardness salts are
Calcium Carbonate and Magnesium Carbonate. Usually tests for hardness
express the result as mg/litre (parts per million) all as Calcium
Carbonate. If there is too little in your water then calcium salts
from concrete, tile grout and other metals in the pool structure
will dissolve in it. Soft water is therefore corrosive. Too much
on the other hand will form scale. Generally the water should
be kept at around 225 - 250 p.p.m as Calcium Carbonate unless your pool
supplier recommends otherwise based on how it is constructed.
If your test shows additions should be made, use Hardness Increase
as as indicated by this calculator.
