SANITIZERS

Sanitizers are added to the water to control the growth of pathogenic (disease causing) bacteria. There are only two "stand-alone" options proven to accomplish this task. Both are represented in products that BioGuard® uses to sanitize pools:

(NOTE FROM POOL EMPORIUM, INC.: Some of this stuff gets pretty technical. DON'T GET HUNG UP ON THE TECHNICALITIES! It was necessary for this information to included so that other sections would make sense.)

• Halogens - A naturally occurring family of electronegative elements that are toxic to microorganisms by interrupting the enzymatic reactions of bacteria and algae. Chlorine and bromine are also powerful oxidizers. (Note from Pool Emporium, Inc.: Chlorine and Bromine belong to this family of halogens as sanitizers as well as oxidizers.)
• Biguanide - A synthetic polymer compound that readily attracts bacteria, there by disrupting the cellular activity. Biguanide polymers are not oxidizers.

Before we discuss these two types of sanitizers it is important to understand why we called these two "stand-alone" sanitizers. Stand-alone means that the biocidal activity (the verifiable mechanism of chemical reactions that, by whatever means, serves to control the growth of living biological organisms) of their chemistry will, by itself, provide control over the growth of bacteria. As such, the Environmental Protection Agency recognizes them as effective methods for use in pool and spa water without the need for additional support chemistry. Let's continue with the most popular family of sanitizers, the Halogens.

CHLORINE - THE MOST POPULAR SANITIZER

Over 90% of all pools (commercial and residential) in operation today use some form of chlorine as a sanitizer. That's because it's highly effective. When chlorine (Cl) is added to water (HOH - a.k.a. H20), it forms Hypochlorous Acid (HOCl), a very aggressive and efficient disinfectant. (Note from Pool Emporium, Inc.: Try to remember this - HOCl is the combination of chlorine and water. There are several references to HOCl throughout this documentation.)

When we test for this compound in pool water, we refer to it as Free Available Chlorine (FAC), meaning it is free and available to kill bacteria.

FREE AVAILABLE CHLORINE (FAC)

HOCI (FAC) kills bacteria very effectively. First it eats through the cell wall by disrupting the enzymes in the cell wall. Then it consumes the inside of the cell via oxidation. Of course, you have to maintain enough FAC to control the amount of bacteria in a given pool. But all pools need to keep FAC within the acceptable range.

HOCI / FAC = 1 - 3 ppm

(NOTE FROM POOL EMPORIUM, INC.: In Florida, we could never keep a clear, blue pool with a FAC [Free Available Chlorine] level of 1.0 ppm, when there is no other supplemental sanitizer present. We suggest 1.5-3.0 in the "winter" [November through March] and 2.0-3.0 in the "summer" [April through October].)

So what is a ppm?

Parts per million is a unit of measurement used in measuring chemical application, it indicates the amount, by weight, of a chemical in relation to one million parts, by weight, of water.

Two types of chlorine are available, they are categorized based on their vulnerability to the Ultra Violet (UV) rays of the sun.

What does Inorganic and Organic mean?

All organic compounds contain carbon. Organic chlorine compounds are characterized by the presence of cyanuric acid (the carbon containing '"stabilizer") to protect the HOCI from the UV rays of the sun.

We'll discuss the types of stabilized chlorine, and their characteristics, first lets take a look at unstabilized (Inorganic) chlorine.

UNSTABILIZED CHLORINE

Any chlorine introduced into a pool forms hypochlorous acid (HOCI) to kill bacteria. However, HOCI is vulnerable to the Ultra Violet (UV) rays of the sun. For every 35 minutes the pool is exposed to the sun, the water will lose half of HOCl present. So even if you start with a FAC (Free Available Chlorine) level of three ppm, which is the top of the ideal range, the unstabilized HOCI would be .75 ppm, which is below the recommended range, in just 70 minutes from the effect of the sunlight alone.

As a result, frequent applications of unstabilized chlorine are necessary in order to maintain FAC in the recommended range. If you choose unstabilized chlorine as your sanitizer, you must check and adjust FAC at least once a day, every day. Typically, the choice to use unstabilized chlorine isn't based on a good understanding of the different types of chlorine. Many pool owners think all chlorine is the same. And since unstabilized chlorine is generally much less expensive (per pound) than the stabilized forms, an uneducated choice is made to use an unstabilized form of chlorine on a regular basis. The result of this choice leads to problems associated with low, or no, Free Available Chlorine in the water.

THE INCOMPATIBILITY PROBLEM

By their chemical nature, organic chlorine and inorganic chlorine are incompatible. Additionally, some forms of unstabilized chlorine are extremely reactive. They cause fire or explosion if mixed with any form of stabilized chlorine or with just about any type of oil or liquid. For example:

A pool owner who has been using 1" stabilized chlorine tablets in his chlorinator, decides, for what ever reason, to buy the cheaper (unstabilized) chlorine tablets from some other supplier. He thinks all one inch chlorine tablets are the same and fills his chlorinator with these other tablets. The reaction between the two different forms of chlorine is so violent, the chlorinator explodes and all the connective PVC plumbing is shattered into hundreds of pieces.

Hundreds of accidents a year are attributed to the fact that either users do not know any better or they don't appreciate the consequences of mixing different chemicals together.

(IMPORTANT NOTE FROM POOL EMPORIUM, INC.: You should never put regular chlorine tablets or sticks into your skimmer. Even after the pool turns off, the tablets/sticks will continue to dissolve, although at a slower rate. The pH of tablets/sticks is very low and corrosive. After sitting in your skimmer between cycles, it creates several gallons of corrosive solution. When your pump turns on for the next cycle, this corrosive solution shoots through all the metal parts in your system, and into your pool. Over time, this could cause damage to those metal parts, as well as premature surface deterioration where that water contacts the pool surface Additionally, this solution could "bleed" out into the pool from the skimmer, while stagnant, and cause discolorations. If you would like to put your chlorine into your skimmer, make sure you are using only BioGuard® Smart Sticks, which were specially formulated just for this type of application.)

STABILIZER

Stabilizer is an organic compound that protects chlorine from the sun. It is also known as Cyanuric Acid (CYA) and is sometimes referred to as "conditioner."

When an HOCI molecule is attached to a stabilizer molecule, it is safe from the UV rays of the sun. However, while attached to the stabilizer, the HOCI does not kill bacteria. So HOCl only works when it's moving between stabilizer molecules. The ideal level of CYA provides plenty of opportunities for protection of the HOCl from UV rays while leaving enough room for the HOCI to move efficiently, encountering and killing bacteria.

Minimum CYA Level: 30 - 40 ppm
Acceptable CYA Range: 30 - 200 ppm
Maximum CYA Level (Commercial Pool) - ? ppm*

(Note from Pool Emporium, Inc.: In Florida, 30 ppm is not usually sufficient and is further driven downwards by some of the torrential downpours we frequently experience. We suggest a minimum of 40 in the "summer" (April through October) and a minimum of 50 in the "winter" (November through March). It may not seem to make sense that we maintain a lower level in the summer, when we are more likely to experience these rains. However, you need to consider the fact that we use much more chlorine in the summer, therefore feeding much more CYA into the pool as well.)

*The maximum CYA level in commercial pools is a parameter established by your local health departments.

Customers using unstabilized chlorine to kill bacteria can extend the life expectancy and efficiency of the FAC by adding Stabilizer 100™ to outdoor pools. (Indoor pools are usually not exposed to the UV rays of the sun and, consequently, do not need stabilizer.)

(Note from Pool Emporium, Inc.: We've seen customers add stabilizer when not needed, and testing stabilizer accurately requires expensive, precision instrumentation. Most pool stores do not have this capability, but Pool Emporium, Inc. does! Please do not add stabilizer unless instructed to do so by a pool professional.)

STABILIZER + CHLORINE = STABILIZED CHLORINE

Rather than add a separate stabilizer, most pool owners prefer the convenience of a sanitizer that contains both chlorine and stabilizer. The best stabilized chlorine for sanitizing is the kind found in BioGuard® tablets and sticks. Its strong formula dissolves slowly and completely. This makes it perfect to compress into sticks or tablets.

HOW TO ADD STABILIZER

Pour the granules through the skimmer with the pump running. Allow the pump and filter to run at least 24 hours before cleaning the filter. (Note from Pool Emporium, Inc.: This can be accomplished by allowing the pool to run for 24 hours straight, or by maintaining the normal run hours, without cleaning the filter, until the pool has run a combined total of 24 hours after the addition of the stabilizer.) Stabilizer dissolves very slowly (which is why the skimmer application method is preferred) and if the filter is cleaned too soon after application, the Stabilizer 100 will be washed out of the filter before it has a chance to dissolve.

The information on this page has been provided courtesy of BioLab, Inc. ©1998