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P/N 471048 Rev. G 1-22-04
12
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CHEMICAL BALANCE
POOL AND SPA WATER
Your Pentair Pool Products pool heater was designed
specifically for your spa or pool and will give you many
years of trouble free service provided you keep your
water chemistry in proper condition.
Three major items that can cause problems with your
pool heater are improper pH, disinfectant residual, and
total alkalinity. These items, if not kept properly bal-
anced, can shorten the life of the heater and cause
permanent damage.
WHAT A DISINFECTANT DOES
Two pool guests you do not want are algae and bacteria.
To get rid of them and make pool water sanitary for
swimming - as well as to improve the water's taste, odor
and clarity - some sort of disinfectant must be used.
Chlorine and bromine are universally approved by health
authorities and are accepted disinfecting agents for
bacteria control.
WHAT IS A DISINFECTANT
RESIDUAL?
When you add chlorine or bromine to the pool water, a
portion of the disinfectant will be consumed in the
process of destroying bacteria, algae and other oxidiz-
able materials. The disinfectant remaining is called
chlorine residual or bromine residual. You can deter-
mine the disinfectant residual of your pool water with a
reliable test kit, available from your local pool supply
store.
You must maintain a disinfectant residual level adequate
enough to assure a continuous kill of bacteria or virus
introduced into pool water by swimmers, through the air,
from dust, rain or other sources.
It is wise to test pool water regularly. Never allow
chlorine residual to drop below 0.6 ppm (parts per
million). The minimum level for effective chlorine or
bromine residual is 1.4 ppm.
pH - The term pH refers to the acid/alkaline balance of
water expressed on a numerical scale from 0 to 14. A test
kit for measuring pH balance of your pool water is avail-
able from your local pool supply store; see Table 1.
Maintenance (contd.)
RULE: 7.4 to 7.6 is a desirable pH range. It is essential
to maintain correct pH, see Table 2.
If pH becomes too high (over alkaline), it
has these effects:
1. Greatly lowers the ability of chlorine to destroy
bacteria and algae.
2. Water becomes cloudy.
3. There is more danger of scale formation on the
plaster or in the heat exchanger.
4. Filter elements may become blocked.
If pH is too low (over acid) the following
conditions may occur:
1. Excessive eye burn or skin irritation.
2. Etching of the plaster.
3. Corrosion of metal fixtures in the filtration and
recirculation system, which may create brown, blue,
green, or sometimes almost black stains on the
plaster.
4. Corrosion of copper in the heater, which may cause
leaks.
5. If you have a sand and gravel filter, the alum used as
a filter aid may dissolve and pass through the filter.
CAUTION: Do not test for pH when the chlorine
residual is 3.0 ppm or higher, or bromine residual
is 6.0 ppm or higher. See your local pool supply
store for help in properly balancing your water
chemistry.
RULE: Chemicals that are acid lower pH. Chemicals
that are alkaline raise pH.
Heat exchanger damage resulting from chemical
imbalance is not covered by the warranty.
CAUTION
Muriatic Acid has a pH of about 0. Pure water is 7
(neutral). Weak Lye solution have a pH of 13-14.
pH Chart
Table 1.
Strongly Acid Neutral Strongly Alkaline
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
ALKALINITY High - Low:
"Total alkalinity" is a measurement of the total amount
of alkaline chemicals in the water, and control pH to a
great degree. (It is not the same as pH which refers
merely to the relative alkalinity/acidity balance.) Your
pool water's total alkalinity should be 100 - 140 ppm to
permit easier pH control.
A total alkalinity test is simple to perform with a
reliable test kit. You will need to test about once a
week and make proper adjustments until alkalinity is
in the proper range. Then, test only once every month
or so to be sure it is being maintained. See your local
pool dealer for help in properly balancing the water
chemistry.
7.2
6.8 7.0
7.4 7.6
7.8 8.0 8.2 8.4
Add Soda, Ash or
Sodium Bicarbonate
Add AcidMarginalIdealMarginal
pH Control Chart
Table 2.