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See pages 44-45 for ph treatment charts, High ph ® acid demand low ph ® base demand – LaMotte Pool Manager Water Quality Handbook User Manual

Page 14

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The pool water pH should be tested several times a day
in a public pool with moderate-to-heavy swimmer usage.
The pool’s pH level is constantly being changed by
chlorine or other treatment chemical additions.
Swimmer usage, additions of fresh make-up water,
leaves, and debris can also alter the pH slightly.
The obvious reason to test pH is not only to identify a
problem but to accurately decide how to remedy the
problem. If a water test reveals a highly basic pH, such as
8.2, then the water supply needs to have an acidic
substance added to bring the water back down to a pH
of about 7.4. This need is called an “acid demand” and
can be corrected by adding a liquid acid (muriatic acid)
or a dry acid (sodium bisulfate).
If a water test shows an acidic pH level, such as 6.8, then
a basic substance should be added to bring the water
back up to a pH of about 7.6. This need is called a “base
demand” and can be corrected by adding soda ash
(sodium carbonate) to the water.

High pH

®

Acid Demand

Low pH

®

Base Demand

See pages 44-45 for pH treatment charts.

12

pH

LOW

If pH is too low (Acidic)




corrosion of pool equipment/staining

swimming eye irritation

etching plaster pool surfaces

chlorine dissipates quickly

pH

HIGH

If pH is too high (Basic)




scale accumulates on pool equipment

cloudy, turbid water

chlorine sanitizing power is weakened

swimmer eye irritation