WATER CHEMISTRY
Water is water, isn’t it? If I can drink the water, why can’t I swim in it? These are good questions,
but the answers may not be simple. As you remember from chemistry in school, all water starts as
H20. But what happens after that is why all water is not the same. If the water comes from a well,
there are usually minerals and metals dissolved in the water because of the soil conditions we
have. If the water comes from a municipal source, there may be chlorine, fluoride, and other
compounds added to the water.
Water that comes from you tap may be safe to drink, but is probably not safe to swim in. When
you fill the pool, the water should not have any bacteria, germs, or algae present. However
exposing that water to the air, sunlight, and to swimmers, greatly changes the water. Many items
are manageable in water to make it safe to swim.
WATER BALANCE
Water Balance is a term used to describe the condition of the pool water when all the factors such
as pH, total alkalinity, calcium hardness, total dissolved solids, copper, iron, and manganese along
with temperature of the water are in their proper relationship. Water Balance is measured by a
formula called Langlier’s Index. The ideal index reading is 0. A significant plus reading will cause
scaling and cloudy water. A significant minus reading will cause etching, wrinkles in liners, and
“red eye” in swimmers.

pH
The term pH is a chemical symbol measuring the potential of hydrogen expressing the acid to base
ratio of the water in the pool. The pH scale reads from 0 to14 with midpoint of 7 being neutral
(neither acidic or caustic). What new owners have trouble remembering is that this scale is
logarithmic and not numerical. This means when you move from the neutral 7 up to the reading of
8, you have not increased the amount of caustic in the water one time, but many times!

TOTAL ALKALINITY
Total alkalinity is the measurement of the carbonate, bicarbonate, and certain other alkaline
(caustic) chemicals in the water. The desired range is between 80 and 150 PPM. A low total
alkalinity reading increases the sensitivity of pH changes in the water. This will allow the pH to
“bounce” up and down. This is not good for the pool or the equipment. If the total alkalinity is high,
the water will be cloudy and will use a lot more of the sanitizer.

CALCIUM HARDNESS
Calcium Hardness is the measure of the combined calcium ions present in the pool water. The
ideal range is 200 to 300 PPM. A low calcium hardness concentration will cause the water to be a
pale clear green and in the case of a plastered pool the water will actually attack the plaster. A
high calcium hardness concentration will cause cloudy water and a very high concentration will
cause the water to be a milky white.
STABILIZER
Stabilizer is a white powder called Cyanuric Acid. Stabilizer does not help in disinfecting or algae
kill, but in the right concentration stabilizer greatly aids in reducing the chlorine demand of the
water. Bright sunlight can draw the chlorine concentration out of a pool within a matter of a few
hours. You could have the correct chlorine reading in the morning and a green pool in the
afternoon if the correct amount of stabilizer is not in the water – 30 to 40 ppm. range.

CHLORINE
Chlorine comes in all types, concentrations, and container sizes. The effective sanitizer is the
hydrochlorous ion that is part of the molecule of the different chlorine sanitizers. Chlorine is a mix
of organic or inorganic compounds and varies from a concentration of 5% such as NaOHCl2
(bleach) to 99% C3N3O3Cl3 (Trichloro-S-Triazinetrione). Not only does chlorine vary in “strength”
but different chlorine compounds dissolve at different rates, have different pH values, and most
importantly, have different uses. There is a section listing the different chemical formulas for
sanitizers and their properties and uses later on in this booklet. Treat all chemicals with utmost
care and follow the label instructions exactly! NEVER PUT ANY TYPE OF NON-STABILIZED
CHLORINE IN A FEEDER! IT CAN EXPLODE WHEN MIXED WITH WATER!

WATER CLARITY
Most new owners start out okay, but then things go wrong! There are so many things to remember
and so many variables such as weather, wind, bather load, and more people other than new
owners get confused. It is better to understand what is going on and what to do to prevent “yucky”
water than to spend your time and money trying to correct it!
Every pool owner experiences cloudy or green water. This is a given fact. The question is always,
“What did I do wrong?” You may have done nothing wrong, but you failed to do some additional
step that would have prevented the cloudy water.
First let us say that each pool is unique. We can only talk in general terms and you should feel
free to bring your quart of pool water to our lab at any time.
Cloudy water usually happens when there has been a change in the weather such as a rain storm,
after a swimming party, or after you have followed the same routine for an extended period of time.
Two things prevent cloudy water - Chemicals in the proper amounts, and the correct filtration.
Saving money by not shocking the pool after a rain or a pool party will actually cost you more when
you have to clean up the mess. Not running the pump twenty-four hours after a rain, party, or
shock treatment will almost guarantee cloudy water. So you see, it is not really something you did
wrong. It is what you did not do. You do not shorten the life of the pump by allowing it to run
twenty-four hours per day. If the filter does not have a chance to do its job of removing the dirt
from the water, no amount of chemicals will keep the pool clean and inviting for long. In the
summer, you probably need to run the pump and filter a minimum of twelve hours a day. At the
first sign of any changes in the water, you must run the pump and filter all the time – twenty-four
hours per day!
Trying to save money by not using the correct dosages of chemicals or running the pump is foolish!
You will certainly spend more money cleaning it up than you saved.