Unstabilized chlorine sanitizers are very effective at killing algae and pathogens that cause diseases in swimming pools. Still there are some parasites that are not easily controlled by all swimming pool chemicals. Some of these parasites include Giardia and Cryptosporidium.
Swimming pool chemicals that are considered unstable, do not contain any carbon atoms in them.
Since these pool chemicals do not have any carbon atoms, they are referred to as inorganic swimming pool disinfectants.
Unstabilized chlorine sanitizers are very sensitive to the ultraviolet radiation found in natural sunlight.
This means that the strength of the chlorine residuals or free chlorine is quickly lost during hot sunny days.
Swimming pool disinfectants that fall under the unstabilized chlorine category include....
Sodium Hypochlorite. This chlorine based swimming pool sanitizer, is the most commonly used disinfectant in public or commercial pool care today. The active strength of this pool chemical ranges from between 10% and 12% with a pH range of 13. Sodium Hypochlorite will raise the total dissolved solids (TDS) and the pH level of your swimming pool or spa water. Total dissolved solids or TDS, are the total weight of all soluble matter in your pool water.
In other words, all dissolved solids that are added to your pool or spa water, contributes to your TDS levels . Although sodium Hypochlorite is a contributor to your TDS levels, it will not have any negative effects on your swimming pool sanitation. Unstabilized chlorine chemicals like sodium Hypochlorite are not very stable when in storage.
This means that they will loose their strength gradually. The lost in strength reduces the benefits of this chemical (sodium Hypochlorite) economically. This happens especially at very high temperatures and the for this reason, manufacturers recommend that you store this swimming pool chemical in a very safe and cool area.
Calcium Hypochlorite. This swimming pool chemical is a dry form of chlorine. It is often referred to as cal-hypo. As a pool or spa owner/operator, you have the option of purchasing this particular pool sanitizer in either granular, tablet, or briquette forms. The active strength for this member of unstabilized chlorine sanitizers, ranges from 65% - 78% with a pH that ranges from 8.5 to 11.
Calcium Hypochlorite is a pool disinfectant that is mostly used for superchlorination in swimming pool care. It is also good for use as the primary disinfectant in erosion feeders. Still you have to be very careful when using this unstabilized chlorine sanitizer because you can raise your chlorine levels significantly as well.
One pound of cal-hypo that has either 65 or 78 percent active strength, can raise your ppm (parts per million) levels up to 7.8 or 9.4 respectively. If you use this pool sanitizer continuously, the balance of your pool or spa water will be affected due to high calcium levels.
For those of us that live in areas where our make-up water is hard, high levels of calcium can result in the formation of scaling.
This scale build-up can be seen in several places in your aquatic facilities. They include:
However if you live in an area where your make-up water is soft, then cal-hypo will be of great benefit to you.
It adds calcium hardness to the water. This is beneficial how you ask? Well, it adds to the overall balance of your swimming pool chemistry.
According to the National Fire Protection Association, this member of the unstabilized chlorine sanitizers regiment, is classified as a class 3 oxidizer.
This means that it can accelerate severely and ignite, if it ever becomes contaminated or heated. Cal-hypo is incompatible with organic compounds, therefore you should take extreme caution when storing and handling this particular pool disinfectant.
Lithium Hypochlorite (LiOCL). Again this is a dry, granular form of chlorine that is used in swimming pool sanitation. It is an excellent choice for superchlorination of your pools as well because it is completely soluble and it responds quickly. The active strength of this chlorine based chemical, is 29% and it has a pH range of 10.8
Lithium Hypochlorite is not commonly used as a treatment in commercial swimming pool facilities. This is simply due to the fact that it has a very low active strength. Still because this pool and spa sanitizer dissolves very quickly, makes it ideal for disinfection in:
Lithium Hypochlorite can also be a good source of treatment in spa water care and in regions that have extremely hard water. Again this member of the unstabilized chlorine sanitizers, has been classified as a class 1 oxidizer. This means that combustion of this pool and spa chemical can be accelerated; thus, it can ignite if it is contaminated or heated.
Chlorine Gas. The active strength of this pool disinfectant is 100% and it has a pH range of zero. Chlorine gas is a great swimming pool sanitizer but it rapidly lowers the pH of your water. This process actively destroys the buffering capability of your pool water. It means that you can not use this pool sanitizer by itself.
You have to use another pool or spa chemical to bring up or maintain the pH level of your water.
Chemicals that are commonly used to raise the pH level in a pool or spa include:
Over the years, the number of swimming pool facilities that use chlorine gas as their means of disinfection, have diminished. This is irregardless of the low cost and effectiveness of this pool disinfectant. The real reasons for the reduced use of chlorine gas are:
Because this chemical is a member of the unstabilized chlorine sanitizers, you will have to use a stabilizer like Cyanuric Acid to protect your chlorine residual.
This is a necessary procedure because in direct sunlight, chlorine based chemicals that are unstable will quickly dissipate.
In other words, without any form of stabilizer, your chlorine content can be completely destroyed in less than an hour. As a result of this, your free chlorine concentrations can fall well below the recommended level of 1 to 3 ppm. As we all know, low levels of disinfectants in a swimming pool or spa will raise the risks of waterborne diseases and swimming pool contamination.
Something to remember here! Cyanuric acid has no sanitation or disinfectant capabilities. Its only function, is to stabilize your free chlorine concentrations in the water. It will not stabilize bromine. So as you can see, with a little precaution and a good stabilizer, you can effectively disinfect your pool with unstabilized chlorine sanitizers.