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Definitions Pool
water chemistry is the most misunderstood, yet vital
component to overall pool care. Not only does proper water
chemistry protect the swimmers using the pool, but it also
protects the swimming pool itself. Gas heaters, electrical
heat-pumps, filters, and even the vinyl-liner can all suffer
severe damage from unbalanced pool water. In order to clear
up some of the confusion surrounding this subject, we have
listed some of the more important water chemistry terms
below.
Total
Hardness
Total Hardness refers to the amount of calcium
and magnesium in your pool water. When total hardness is too
high, scale can form causing the water to appear cloudy.
When total hardness is too low, the water will corrode metal
fixtures including copper components found in gas heaters
and electrical heat-pumps. The total hardness should
measure 150 - 300 ppm.
Chlorine
Chlorine is a disinfectant designed to sanitize
(kill disease-causing organisms) and oxidize (destroy
ammonia, nitrogen-containing contaminants and swimmer
waste). A disinfectant must be continually active in the
pool water so that it may react instantaneously with
bacteria, algae and other organic matter as they are
introduced into the water. The level of active chlorine is
called the free chlorine residual and should measure 1.5 -
3.0 ppm.
Total
Alkalinity
Total Alkalinity measures the amount of alkaline
substances in the pool water. Alkaline substances buffer
your water against sudden changes in the pH. When the
total alkalinity is too low, the water will corrode metal
fixtures including copper components found in gas heaters
and electrical heat-pumps. Low total alkalinity could also
cause staining and weaken your vinyl liner, causing it to
wrinkle. The total alkalinity should measure 80 ppm for
swimming pools using granular chlorine, or 100 - 120 ppm for
swimming pools using stabilized chlorine such as chlorine
tablets.
pH
pH refers to the intensity of acid or alkaline
materials in your pool water. pH is measured on a pH scale
extending from 1 (extremely acidic) to 14 (extremely
alkaline). A pH of 7.0 is considered to be neutral. High pH
(higher than 7.8) can cause eye and skin irritation, reduce
the sanitizing action of chlorine, and cause the water to
appear cloudy. Low pH (less than 7.2) can cause eye and skin
irritation and corrode metal fixtures including copper
components found in gas heaters and electrical heat-pumps.
The pH should measure 7.2 - 7.8.
Cyanuric
Acid (Chlorine Stabilizer)
Cyanuric acid lengthens the life of chlorine in
the pool water. Chlorine products that contain cyanuric acid
as an ingredient are referred to as "stabilized chlorine".
These types of chlorine are used to maintain consistent
levels of chlorine in the pool water. But they are not very
effective at clearing cloudy water or killing algae. For
pools that use "non-stabilized chlorine", that is chlorine
that does not have cyanuric acid as an ingredient, cyanuric
acid should be added in the spring when the pool is clear
and the water is balanced. The cyanuric acid level should
measure 40-80 ppm.
Pool Water
Problems and Solutions
Cloudy Water
Pool water can turn cloudy for a variety of
reasons. The most common cause of cloudy water is either
dead algae floating in the pool water or other small
particles floating in the water such as dissolved leaves.
The best way to treat a cloudy pool is chlorine, chlorine,
and more chlorine. You should add a large dose of
non-stabilized chlorine (either calcium hypochlorite or
sodium hypochlorite) each day for four to five days
straight, keeping your free chlorine level above 3 ppm at
all times and running the pool filter 24 hours a day. If
this does not clear your water, then you can try clarifiers
and other products. But first shock your pool water.
Algae
Algae are microscopic plants which can transform your pool
water from clear blue to a swamp in as little as 24 hours.
Algae spores are introduced into the pool through the air,
from rain water, and from swimmers walking across the grass
and then jumping into the pool. Algae blooms are common
after heavy rain showers and when the pool water temperature
is high. There are many types of algae, the most common in
our area being green algae, mustard algae, and black algae.
The most effective way of preventing algae growth is to
maintain a free chlorine level of at least 1.5 ppm at all
times, run the pool filter 24 hours a day, and to add a dose
of algaecide once a week. We have also found that adding Sun
Algaecide to the pool water decreases your chances of
suffering from an algae bloom. a Sun Algaecide acts as an
inhibitor against algae growth by lowering algae's ability
to process carbon dioxide in the water making it difficult
for an algae spore to germinate and grow. If you do develop
algae, apply the appropriate algaecide, shock the pool, and
brush down the entire pool causing the algae to become
suspended in the pool water. The next day, if anything
settles out, vac it out to "Waste".
Tinted Water and Stains
If minerals are present in the pool water, they can cause
the pool water to turn green, brown, yellow, and even
purple. The water would look clear but discolored. It can be
very difficult to distinguish between green water caused by
green algae and green water caused by a mineral problem. A
telltale sign of a mineral problem is the discoloring of the
pool water shortly after shocking the pool. If this occurs,
you will need to add a mineral sequester to the pool.
Exactly how much is a guess. We have seen cases where one
bottle has solved the problem, and others where multiple
bottles were needed. Mineral problems are a tough nut to
crack and the pool industry is just now trying to get a
handle on it. Stains on the vinyl liner are also treated by
adding a mineral sequester. Persistent stains might need to
be treated with an "on contact" product that must be applied
directly to the stained area of the pool. If the stain is on
the bottom of the pool, applying the product directly on the
stain can be tricky, but possible.
Low pH
Due to the acidic nature of our tap water and our
rain, we tend to suffer more from low pH pool water than
from high pH pool water. Fortunately, correcting the pH
balance of your pool water is quite simple. All you need to
do is add pH Increaser (also called soda ash and base). But
before you
add pH
Increaser be sure to get your Total Alkalinity balanced
first. Once the Total Alkalinity is balanced, the pH can be
adjusted more accurately. |
