Pool Controls Ozone XLM Series User Manual page 6

Chlorine
If it is a new installation, add enough chlorine (liquid or granular) to achieve a reading of
3ppm on an appropriate test kit.
Stabiliser
If the pool is outdoors, it is vital that stabiliser (also known as cyanurate and cyanuric acid)
be added and maintained at 50ppm. This compound reduces chlorine destruction due to
sunlight. However, too much stabiliser will reduce the effectiveness of chlorine and can
result in poor quality water so ensure stabiliser does not exceed 80ppm.
pH
For chlorine to be effective, the pH must be within a certain range. This is usually between
6.8 (fibreglass/liner pools) or 7.2 (concrete/plaster) and 7.8.
Adjust pH down with acid – powder, liquid sulphuric or liquid hydrochloric (preferred). Be
very careful with acid as it can be harmful and corrosive.
Minerals: the magnesium in mineral salts can form a soft scale on the cell even though it
is reversing polarity. This is minimised by keeping the pH at the lower range for your pool
type. The use of hydrochloric acid is recommended for magnesium mineral systems.
Total Alkalinity (TA)
Total alkalinity is also known as carbonate hardness or TA for short. The recommended
level is between 80 and 120ppm.
TA is related to pH in that it stops the pH from varying quickly with small additions of acidic
or alkaline chemicals. When the TA is low it is almost impossible to control the pH. To
raise the TA, buffer (sodium bicarbonate) is added. This must be done slowly as buffer will
also cause the pH to rise. As an approximate rule every increase of 20ppm of TA will also
cause a 0.1 rise in pH. Once buffer is added it should be left to mix in the pool for a few
hours before reducing the pH.
Phosphates and Nitrates
Phosphate and ammonia nitrogen will make your garden green – and they will do the same
thing to your pool. Check for phosphates and add phosphate remover if necessary. Don't
let fertiliser get into your pool! Phosphates are also in some cleaning products – check the
label if using around your pool.
Pool Cover Blankets
Most of the chlorine demand for a pool comes from the action of sunlight on the chlorinated
water. When a cover blanket is used it is possible for the chlorine residual to build up to a
higher level that can be damaging to the blanket and possibly the pool and fittings.
This unit can adjust the output to compensate for the use of a cover blanket – simply push
the button and the display will flash COVER. While the cover is on the chlorine output will
be reduced. When the cover blanket is removed simply push the button again and the unit
will revert to its normal chlorine output.
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