TERM
DEFINITION
Potential Hydro-
gen
(pH)
The pH level is the measure of alkalinity.
pH is measured between 0 and 14 denoting various degrees of acidity or alkalinity.
Neutral water has a pH of 7.0 Water below 7.0 is acidic and becomes more acidic as it approaches zero.
Water above 7.0 is alkaline and alkalinity increases as it approaches 14.
When the pH of water is 7.0 or below, chlorine will act primarily as a sanitizer. At this level, it is very effective at
killing bacteria.
At 7.4, chlorine will act equally as a sanitizer and oxidizer.
Above 7.8, chlorine will act principally as an oxidizer.
The pH of chlorine is 11.7ppm.
Spa water is considered balanced if the pH level is within the target range, between 7.2pH to
7.6pH.
Adding chlorine either automatically through a salt system or manually, into spa water with high pH, above 7.6pH,
will further increase the pH level and dramatically reduce the effectiveness of the chlorine as a
sanitizer.
This must be avoided by first reducing the pH level into the target range 7.2pH - 7.6pH.
The chart below reflects the loss of sanitizer effectiveness/sanitizer effectiveness based on the spas water pH level:
pH Level
Sanitizer (Chlorine)
Loss of Effectiveness
based on pH Level
Sanitizer (Chlorine)
Effectiveness
based on pH Level
7.0 pH
27%
73%
7.2 pH
38%
62%
7.5 pH
50%
50%
8.0 pH
78%
21%
8.5 pH
90%
10%
6.0 pH
4%
96%
6.5 pH
10%
90%
Maintaining a Balanced pH level between 7.2pH and 7.6pH is extremely important for:
• Optimizing the effectiveness of the sanitizer.
• Maintaining water that is comfortable for the user.
• Preventing equipment deterioration.
• Note: Salt systems naturally drive pH levels to increase, strive to achieve a balanced pH level.
If the spa water’s pH level is too low, the following may result:
• The sanitizer will dissipate rapidly.
• The water may become irritation to spa users.
• The spa’s equipment may corrode reducing life expectancy.
Low pH can be raised by adding Arctic Pure, Adjust Up to the spa water.
If the pH level is too high, the following may result:
• The sanitizer is less effective.
• Scale will form on the spa shell surface and the equipment.
• High pH will cause calcium to precipitate (fall out of suspension).
• The water may become cloudy.
High pH
can be lowered by adding
Arctic Pure, Salt Water Balance
to the spa water.
It is important to check the pH on a regular basis. The pH will be affected by the bather load, the addition of new water, the
addition of various chemicals, and the type of sanitizer used.
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