Understanding Swimming Pool Chemicals/Water Balance

Understanding the basics of water chemistry is extremely important. One of the most
important things I’ve found over the years is that for every action there truly is an equal
or greater reaction. For example, when you add chlorine to your pool you’re also
changing other chemical elements. This is not such a bad thing, but the important thing is
that we always have to be conscious of “If I do this, what will be the end result and what
else might be effected by this action?”
Let's face it--the only thing essential about a swimming pool is that the water be fresh and
clean. Let's face something else, too: Achieving this can involve more chemistry than you
may have seen since junior year in high school--if then. Don't worry, though. Here are all
the important concepts and terms you need to know to keep your pool clean. Just be sure
to follow all manufacturers’ directions on the package of a chemical carefully.

Here are a few basic tips when it comes to pool chemicals and maintaining water “harmony”:
Note: The three factors mentioned here--pH, total alkalinity and calcium hardness--all
affect one another, so it will take some trial and error to get all three in the proper range
at once. Also note that before you add any chemical--especially an acid--to the water, you
need to first turn on the pool's equipment. Make sure the water is circulating when
adding chemicals!

 

Test for total and free chlorine.
Your free chlorine should be between 2.0 and 4.0 PPM. You’ll test this using your water
test kit that I referenced above. Follow directions on the testing package. Add chlorine if
it’s necessary.

 

Test your total alkalinity
Measure the water's total alkalinity. This figure should be in the range of 80 to 150 ppm;
100 to 120 ppm is best. Adjust the total alkalinity by adding sodium bicarbonate (baking
soda) to raise it or sodium bisulfate (dry acid) to lower it.

Test your calcium hardness. This should be between 200-400 PPM.
Following package directions add calcium carbonate dehydrate to raise calcium hardness; add
sodium hexametaphosphate to lower it. Carefully pour the chemical mixture into the pool at
various spots a foot or two (about half a meter) away from the sides of the pool.

Test for pH. Your pH should be between 7.2 and 7.8.
Just remember, if it’s lower that this you can cause equipment issues and also irritate your
skin. If it’s higher than this you will those nasty “rings” around the water line of your
pool. To lower the pH, add sodium bisulfate or liquid muriatic acid. To raise it, add soda
ash (sodium carbonate).
Add more chemicals as needed until the water is in balance.

Treating Water With Chlorine…
Scoop chlorine granules into water in a nonmetal container, following package directions.
Always wear goggles and rubber gloves when handling chlorine, and always put the
chlorine into the water--don't pour the water over the chlorine.
Stir for about 30 seconds, and leave for 30 minutes to settle.
Turn on the filter. Reaching as far into the middle of the pool as possible (perhaps by
standing on a diving board), pour the chlorine into the pool. Discard any sediment left in
the container.
Add chlorine three to four times a week for a pool in heavy use. Always test your water
before adding chlorine!
If you can, try and use liquid chlorine. It will penetrate the water quicker and will have
an immediate impact!
Occasionally--no more than once a week--you may need to super chlorinate (also called
shock) the pool to burn any built-up bacteria, algae and ammonia. Following chlorine
package directions, make a solution for super chlorination (it will be three to five times as
strong as normal chlorine).

Add the chlorine solution to the pool after sundown, if possible, as the sun's ray’s break
down chlorine.
Before allowing anyone to go in the pool, test the residual chlorine level to make sure it
has gone back down below 3.0 ppm. This will take at least several hours