FAQ's

Frequently Asked Questions
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  • Potable Aqua® FAQs
  • Potable Aqua® Chlorine Dioxide Tablet FAQs
What is Potable Aqua®?
Potable Aqua® Drinking Water Germicidal Tablets make water bacteriologically suitable for drinking. They contain iodine in a proprietary compound called TGHP. Each tablet contains 20 milligrams of TGHP, which liberates 8 milligrams (ppm) of titratable iodine. As indicated by label directions, the recommended dosage of Potable Aqua is two tablets in one liter or quart of water. When the tablet dissolves in water, it releases both free iodine and hypoiodous acid. Both are effective germicidal compounds. Potable Aqua tablets also contain a buffering agent that brings the pH of the water to a slightly acidic level to optimize the disinfecting properties of the iodine.
How does Potable Aqua® work?
Each Potable Aqua tablet contains 20 milligrams of TGHP, which liberates 8 milligrams (ppm) of titratable iodine. Dissolving Potable Aqua tablets in water releases the iodine bound in the TGHP molecule.

When dissolved, both diatomic iodine (I2) and HIO are released. Because the tablets contain a buffer, the treated water is maintained at acidic conditions with an approximate pH level of 5.5. Diatomic iodine is more abundant than hypoiodous acid. This mixture provides adequate disinfection of most waters.

Chemical reaction rates, and consequently germicidal effects, are subject to variables such as water temperature and level of contamination in the water. For this reason, two tablets of Potable Aqua and a 30-minute waiting period are required before drinking the water. The iodine works by penetrating the cell wall of the microorganism, therefore rendering it inactive.
How does Potable Aqua® Chlorine Dioxide work?
Chlorine dioxide, a water-soluble gas, is an extremely effective and powerful biocide that has been used for many years, exhibiting rapid kill over a wide range of organisms. It does not form chlorinated molecules in the presence of organics and is efficacious over a wide pH range.

Although chlorine and chlorine dioxide share the word "chlorine" in their names, their chemistries are very different. Unlike chlorine, chlorine dioxide doesn't chlorinate. It works through oxidation and penetrates bacteria cell walls and reacts with vital amino acids in the cytoplasm of the cell to kill the organism. However for most applications, chlorine dioxide must be produced and used at the same location because the compound is unstable and in large quantities cannot be stored or transported.

Now, Potable Aqua antimicrobial technology allows for the delivery of chlorine dioxide in a stable tablet form. Potable Aqua Chlorine Dioxide Water Purification Tablets produce chlorine dioxide only when they come into contact with water or when they are exposed to moisture in ambient air. When sealed in airtight containers, such as the foil strip packs in which they are contained, they can be stored and used when needed.
How long may I use Potable Aqua®?
Potable Aqua tablets are to be used as a short-term, emergency treatment for disinfecting drinking water. Potable Aqua should not be used on a long-term, continuous basis.

According to label directions, the recommended dosage of Potable Aqua is two tablets in one liter or quart of water. This dosage is equivalent to 16 ppm of elemental iodine in the water. Since this product is intended for use in emergency situations, extended daily use should be kept to a limited basis and not exceed six weeks.
How do I use Potable Aqua®?
Potable Aqua tablets are dissolved in water to form a solution for consumption. Add two tablets to one quart or liter of water. Cap loosely to allow slight leakage and wait five minutes. Shake the container briskly so that a small amount of water seeps out to rinse the screw threads. This will help to disinfect the lip of the container, which may have come into contact with untreated water. Tighten the cap and wait 30 minutes before drinking.
How do I use Potable Aqua® Chlorine Dioxide Tablets?
Use Potable Aqua Chlorine Dioxide Water Purification Tablets to kill bacteria, viruses and cysts (Cryptosporidium parvum and Giardia muris) in contaminated water.

Remove the tablet from its foil packaging with knife or scissors, and quickly insert into one quart (one liter) of contaminated water. Allow to react for 4 hours, in an area away from sunlight, to generate a solution of 4 ppm chlorine dioxide. The treated water is now ready for drinking.
What is the shelf life of Potable Aqua® Tablets?
Unopened bottles of Potable Aqua tablets, when maintained under controlled temperatures between 60 and 86 °F (15 to 30 °C), should remain effective up to four years. Exposure to heat, humidity, moisture, and air will reduce the effectiveness of the tablets. We recommend that an opened bottle not be kept for more than one year. Keep the cap tightly sealed.

Although this product is not required to have an expiration date, an explanation of the lot numbering system is provided for your convenience. This lot number is imprinted on the label of the bottle. Example:
4 03 27
The lot number is a five or six digit number. The first digit(s) represent the month of manufacture. The next two digits represent a two-digit year and the last digits represent a batch number for that month and year. Using the example above, the product was manufactured the 4th month of the year 2003 and was the 27th batch of product made. Under normal storage conditions, this product would be effective for at least four years for an unopened bottle and one year for an opened bottle.

If in the field, check the tablets appearance to determine if they are still effective. If the tablets are gray or dark brown in color, they are still likely to be effective. If they are light green or yellow, it means they are probably no longer effective. The tablets are very sensitive to moisture. Take care that moisture does not get inside the Potable Aqua bottle.
What is the shelf life of Potable Aqua® Chlorine Dioxide Tablets?
The shelf life of Potable Aqua Chlorine Dioxide Water Purification Tablets is 4 years, however it is important to check your package of Potable Aqua for the exact expiration date.
What are the advantages of using Potable Aqua® Tablets?
Potable Aqua has long been considered one of the best germicidal tablets for drinking water on the market. Potable Aqua was developed by the U.S. Military during World War II and is still used by the military today. The Australian Military and The Boy Scouts of America also use it, along with various relief organizations, mission groups and outdoor enthusiasts throughout the world.

Potable Aqua provides an accurate dose, and is effective over extreme conditions such as cloudy water, low temperatures, and extreme pH. It is simple to use, foolproof, and time-efficient. It does not require mixing two parts together, or a waiting period for it to activate before it can be used. Usage is time efficient, and the water is ready to drink in 30 minutes. It does not neutralize or remove chemical contaminants or remove particulate. Potable Aqua may be used in conjunction with a water filter. It is effective against bacteria, viruses, and many cysts such as giardia lamblia. Potable Aqua is not effective against cryptosporidium cysts.

While the iodine may impart a "taste" to the water, this is easily resolved by using PA Plus after the 30-minute disinfection period. PA Plus takes away the taste and odor of the iodine by converting it to colorless and odorless iodide. Iodine is a convenient and effective water purifier.
What are the advantages of using Potable Aqua® Chlorine Dioxide Tablets?
Unlike chlorine, chlorine dioxide does not produce THMs or dioxins; it is convenient to use and can be stored for long periods of time; it kills a wide range of bacteria, viruses and cysts; and it improves the taste and odor of water, rather than presenting a "chlorine smell" or taste. In addition, with 2.6 times the oxidizing capacity of chlorine, chlorine dioxide has demonstrated four-to-seven times greater biocidal activity at equivalent doses.

Among the many advantages offered by Potable Aqua Chlorine Dioxide Water Purification Tablets as compared to alternative antimicrobial agents are:
  • Works against a wide variety of bacteria, yeasts, viruses, fungi, protozoa, spores, molds, mildews, and other microbes.
  • Demonstrated 4-7 times the biocidal activity of sodium hypochlorite at equivalent doses.
  • 2.6 times the oxidizing capacity of chlorine.
  • Actually improves the taste and smell of water.
  • Effective at low concentrations (4PPM) and over a wide pH range.
  • Biodegrades in the environment.
  • Does not generate harmful by-products.
Can Potable Aqua® tablets be repackaged in a different container?
We do not recommend that Potable Aqua tablets be repackaged into any other container. Potable Aqua tablets are manufactured under highly controlled temperature and humidity conditions that minimize exposure to the atmosphere. The tablets are very hygroscopic (i.e. have the ability to attract moisture), which causes them to degrade quickly if exposed to moisture or high humidity.

Potable Aqua is manufactured to strict specifications, and is tested to assure it meets those requirements throughout the manufacturing and packaging process. Even the wadding inside the bottle (which prevents the tablets from getting crushed or crumbling) is a special moisture resistant material. Once a tablet is handled or is outside of its original container, we can no longer guarantee that it will maintain its effectiveness.
What is PA Plus and how does it work?
PA Plus is an ascorbic acid tablet, which removes the taste and odor of iodine after the water is treated with Potable Aqua. The ascorbic acid acts as a reducing agent, converting the iodine to iodide, which has little or no germicidal properties. The iodine is still present, but in a different chemical form which neutralizes the iodine taste and odor. PA Plus should be used AFTER the 30-minute waiting period for Potable Aqua. After using PA Plus, the water does not have any residual ability to kill germs, so take care not to re-contaminate the water. PA Plus tablets disintegrate rapidly and remove the iodine taste and color within three minutes. Each tablet contains approximately 45 milligrams of ascorbic acid (vitamin C). One tablet will easily neutralize two tablets of Potable Aqua.
Can Potable Aqua® tablets be eaten?
Potable Aqua is for use only according to label directions. The tablets are not meant to be ingested or taken whole without being diluted in water. Using this product in a manner other than what it is labeled for is a violation of federal law. Potable Aqua is intended only for the emergency disinfection of water and should not be used in any other way.
Is iodine safe for use in drinking water?
Iodine is an essential element in our diet and is required for proper thyroid function. Too much or too little iodine exposure can affect thyroid function. (Iodine was first documented as a remedy for goiter in 1860. Goiter is a thyroid disorder caused by too little iodine in the diet). In many countries, iodine is added to table salt to insure adequate amounts of dietary iodine.

Iodine is used in various forms as an antiseptic for skin wounds and mucous surfaces of the body. It also is used for sterilization of the air and of inanimate objects such as surgical instruments. It is a prophylactic and therapeutic agent for diseases caused by bacteria, viruses and fungi, and for the disinfection of drinking and swimming pool water, and for the sanitation of eating utensils.

There is always a risk/benefit decision to be made when using any chemical, and the risk of contracting a disease from water of unknown bacteriological content is significant. Based on Pharmacal's 25 years of experience marketing Potable Aqua, there should not be cause for concern in any healthy individual when it is used in accordance to label directions in a short term situation of six weeks or less. Of course, individuals may be more or less sensitive to certain chemicals, and thus may react differently. Consult your physician for more information.
Is chlorine dioxide safe for drinking water?
Yes. As a matter of fact, chlorine dioxide is used in water treated for municipalities. Of course, individuals may be more or less sensitive to certain chemicals, and thus react differently. Consult your physician for more information.
Will iodine affect my thyroid function?
Iodine and thyroid function have been extensively researched by the medical community. Short-term increases or decreases in dietary intake of iodine are accommodated by the normal thyroid gland, and iodine is rapidly metabolized and cleared from the body. Potable Aqua is well-tolerated by individuals with normal thyroid function for use in short-term emergency situations of six weeks or less. Individuals with thyroid problems or pregnant women should consult a physician before using iodine-based products.
Can I take Potable Aqua® tablets while I'm pregnant?
Iodine is an essential element in our diet and is required for proper thyroid function. Too much or too little iodine exposure can affect thyroid function. (Iodine was first documented as a remedy for goiter in 1860. Goiter is a thyroid disorder caused by too little iodine in the diet.) In many countries, iodine is added to table salt to insure adequate amounts of dietary iodine. Iodine is required for the healthy development of the fetus.

Using Potable Aqua as directed on the label for short-term emergency drinking water disinfection is not likely to be deleterious to women or the fetus, but it is recommended that women check with their doctors before using Potable Aqua tablets during pregnancy.
Can I take Potable Aqua® Chlorine Dioxide tablets while I'm pregnant?
Using Potable Aqua Chlorine Dioxide Tablets as directed on the label for short-term emergency drinking water disinfection is not likely to be deleterious to women or the fetus, as chlorine dioxide is commonly used to treat city water, but it is recommended that women check with their doctors before using Potable Aqua Chlorine Dioxide Tablets during their pregnancy.
What organisms are iodine effective against?
Iodine, in the concentration released by Potable Aqua, has been found to kill the following organisms:
  • Escherichia coli
  • Vibrio cholerae
  • Salmonella typhosa
  • Salmonella typhimurium
  • Salmonella paratyphi
  • Shigella dysenteriae
  • Shigella flexneri
  • Shigella sonnei
  • Aerobacter aerogenes
  • Klebsiella terrigena
  • Streptococcus faecalis
  • Leptospira icterohaemmorrhagiae
  • Infectious hepatitis
  • Poliomyelitis
  • Entamoeba histolytica (amobic dysentery)
  • Giardia lamblia (Giardiasis)
  • Schistosome cercariae (aka Bilharzia)
What organisms are Chlorine Dioxide effective against?
Potable Aqua Chlorine Dioxide Tablets are effective against all the same organisms as Iodine, as well as Cryptosporidium cysts.