100% PURE CHLORINE

Gas chlorination is completely legal; operations that handle gas chlorine are required to be EPA registered, and licensed by various state and local agencies. The actual degree of licensing and certification of gas chlorination companies far exceeds that required for any other type of swimming pool service firm.

Absolutely not! Gas chlorine, in contrast to over-the-counter chemicals used in pool water treatment, may only be handled by trained and knowledgeable operators. They make it their business to use a balanced approach and professional knowledge of their product to protect your pool and equipment. The misuse, or improper application of any pool chemical can cause problems for the pool owner; normal "wear and tear" on the pool surface and equipment may be accelerated, and both metals and plaster may be affected. Please refer to the statements from industry professionals at the end of this bulletin in reference to the compatibility of pure chlorine with pool plaster/products. They qualify their statements with the note that the professional will maintain the water chemistry within accepted parameters. As with any chemical, care should be taken to ensure that the pool is balanced properly with regard to pH, alkalinity, and hardness. As the residential use of gas chlorine is limited to specially licensed service firms and should not be obtainable by unlicensed operators, the potential for damage due to improper handling of gas chlorine is far less than that of all other chlorinating compounds - which are available indiscriminately for over-the-counter purchase, with no requirements for training or safety. When making any chemical treatment or service decision for your pool, be sure your service company is knowledgeable about the chemicals they use, is qualified to handle them, and meets all local licensing requirements.

Every chlorinating compound added to disinfect pool water has some effect upon water pH and alkalinity. Since water (especially swimming pool water) is generally alkaline in nature, it is a benefit to use a chlorine product that is acidic, and thus offsets this alkalinity; rather than one which increases it, thereby requiring the addition of liquid acid to avoid scaling. Gas chlorine (the pure form of chlorine) when added to water, interacts with the acid/base balance and can lower pH, depending upon other factors, particularly alkalinity and hardness. This chemical reaction is the same as when muriatic acid or trichlor tablets are used, except for the fact that the change in pH is effected by a diffuse chemical reaction rather than the addition of concentrated chemicals. The effervescence of the gas-created acid spreads gently and broadly throughout a properly buffered pool, as opposed to the strong localized reaction one creates by adding concentrated hydrochloric acid in the form of liquid (muriatic) pool acid. Again, as with any sanitizer system, proper understanding and maintenance of pH and alkalinity is the key to a well balanced pool. Gas chlorinators use buffering agents (like soda ash and baking soda) to balance your pool water and maintain proper equilibrium. This integrated "balance" approach utilized by professional gas applicators uses all pool chemistry factors (such as alkalinity, buffers, and hardness) and pure chemicals (rather than compounds which contain unwanted additives) to create a total balanced effect that never results in overly high or low pH conditions.

Gas chlorine, like virtually all chlorinating compounds, is classified as a hazardous material. The widespread use of gas chlorine in industry and water treatment worldwide makes it one of the most well known chemicals in use today. It also enjoys the distinction of having one of the finest safety records of any chemical. This is primarily the result of stringent handling and use guidelines established by the Chlorine Institute in Washington, D.C. Although the swimming pool industry only accounts for less than 5% of all chlorine used, these guidelines from the Chlorine Institute do cover swimming pool treatment applications. Any chemical that is either mishandled or improperly used is dangerous. However, since residentially-applied gas chlorine is available only to specially trained firms who have to comply with strict safety standards; and, since these firms use relatively small amounts of the product, gas chlorine does not represent a significant hazard.

No. Gas chlorine was briefly tried as a war weapon during World War I, but was quickly replaced as such because it was ineffective for the use. It dissipated too fast, was neither toxic nor persistent enough to do the desired damage to troops, and its effects were too easily remedied. It was therefore quickly replaced by more toxic and effective compounds. In fact, pure gas chlorine was later used in training because troops exposed to it suffered no lasting damage... they recovered quickly and could learn from the experience of relatively benign gas exposure without suffering lasting damage from it.

Please bear with us, because this one gets a little more technical. Total chlorine is a combination of free chlorine and combined chlorine. In pool applications, combined chlorine, or chloramine, is an irritant (to swimmers) and a retardant (for the chlorine's effectiveness) and is therefore an unwanted form. Free chlorine (which for pool purposes includes stabilized chlorine) is the desired sanitizer, and as dictated by pH is further subdivided into free active (HOCl) and free passive (OCl-) chlorine. Free active chlorine is the effective sanitizing agent in the disinfection process, and the passive form is a reserve for when the active form gets used. Most gas chlorination services maintain pH levels between 7.8 and 8.2. At this level, 20 to 30% of the total chlorine is both free and active. When chlorine is added to the pool on the service day, the initial addition creates a super-chlorination, or shock effect in the pool. This is a beneficial way of removing any combined chlorine or impurities in the water. Any chlorine used during this process is said to have satisfied the "chlorine demand" of the water. Any remaining chlorine then becomes free chlorine waiting to be used and is referred to as the chlorine residual. This residual can be thought of as a "bank" of available chlorine in the form of free active and passive chlorine. The active is ready to kill bacteria and algae, and the passive replenishes the active. The amount of chlorine added is carefully calculated to ensure that an adequate residual remains for protection until the next service day. At no time is there an unsafe condition of too little sanitizer and other than a short (20-30 minute) period while blending, at no time is the water unsuitable for enjoyable swimming. The levels of chlorine maintained in this process have been carefully studied, calculated, and documented to achieve the maximum benefit for the pool and swimmers. The fact that chlorine levels fluctuate is true, and this "shock and residual cycle" is maintained intentionally as a benefit. Studies document that a constant low-level dosage of chlorine without regular super-chlorination is a recipe for chloramines and ineffective sanitization. The NSPI recommends super-chlorination at least every other week, and weekly when the water is warm. In general, a gas chlorinator super-chlorinates weekly in the summer. Periodic super-chlorination is a routine that all pool professionals and most pool owners recognize as a necessary practice, particularly in summer months. Super-chlorination coupled with adequate chlorine residuals, in conjunction with proper pH and alkalinity balance, represents better water disinfection, not problems.