I. Introducon
A. Water Chemistry
Water chemistry is a complex science that contains many variables.
These variables not only aect the water environment itself, but
they can have adverse eects on your equipment as well as your
health. These are only some of the factors which we follow closely
to ensure the most healthy water interacons:
pH is the measurement of the acidity or basicity in an aqueous
soluon. A measurement below 7 is considered acid, while a
measurement above 7 is base or alkaline. It is a signicant factor
in determining the water quality as it aects sanizer levels, water
color, and human reacon to the water.
ORP (Oxidaon Reducon Potenal) is the measurement of the
oxidizing capacity present in water. ORP cannot be fooled by the
eects of pH, total dissolved solids (TDS), stabilizers, and non-chlo-
rine oxidizers. A typical ORP sensor measures Hypochlorous Acid
(HOCI), which is the more eecve component of free chlorine. A
higher ORP reading equates to the sanizer working more eec-
vely.
Water balance is comprised of pH, calcium hardness, total alkalin-
ity, temperature, and TDS. When water is balanced, the Langelier
saturaon index is 0. Values above +0.3 lead to scaling and cloudy
water, while values below -0.3 can cause corrosion of pool equip-
ment and surfaces. If the water balance is not xed in a mely
manner, secondary eects can lead to rapidly declining water con-
dions that can aect the health of the water occupants.
pH and ORP work conversely to one another, and are aected by
other factors such as temperature and TDS’ that can increase the
negave impacts of unbalanced water.
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M790 pH/ORP Controller Owner’s Manual
