Chloramines (combined chlorine) & Chlorine Demand...

One of the most common causes of water related problems in spas, hot tubs, and swimming pools is the presence of chloramines.  Chloramines are often referred to as “combined-chlorines” because they are molecules formed by the combination of chlorine in the form of Hypochlorous Acid (HOCl) and organic wastes (saliva, perspiration, urine) in the form nitrogen or ammonia (NH3).  Chloramines or combined chlorines produce the “chlorine odor” that many people do not like (tear gas is a form of Chloramine). When people complain of “too much” chlorine, it is almost always the case of combined chlorine or chloramines causing the foul odor as opposed to a proper level of Free Available Chlorine (FAC).  In other words, there is actually NOT ENOUGH of the proper chlorine present to kill the bacteria.

Please keep in mind that when we are talking about "chlorine" or "bromine" that kills bacteria & algae, we are always talking about Free Available Chlorine or Bromine.  The Free and Total Chlorine should always be equal, about 1.0 - 3.0 ppm chlorine or 4.0 - 6.0 ppm bromine.  If your test gives you a TOTAL chlorine or bromine that is higher, then chloramines or bromamines are present - and you want them out of the water.

But foul chlorine odors are just the ugly mask of the underlying problems present in spa & hot tub water.

Chloramines are the root of many problems in pool water.  Chloramines cause problems because of their stability and persistence.  This stability and persistence forms additional Chloramines.  This is chlorine demand (consumption) at its finest.  (Consumers complain that they “just shocked” the pool but there’s no chlorine showing when tested.) As more chlorine is added without reaching breakpoint, more chloramines are formed thereby exacerbating the problem leading to what I’ll call “obvious problems” such as cloudy water or algae growth.  Homeowners and/or pool dealers unfamiliar with chloramines and chlorine demand begin treating the symptoms (cloudy water or algae) rather than dealing with the root cause – especially after the second or third treatment.  Without the knowledge of chloramines & chlorine demand, consumers may not receive the help they need. 

In some cases, it may be better to drain & refill the spa or hot tub with fresh water.  But be careful -- your fill water may already contain high levels of chloramines.  As you read on you'll see why.

Chlorine demand testing stations aid greatly in determining the appropriate amount of chlorine needed to reach breakpoint chlorination – usually recognized as 10 ppm FAC (free available chlorine) to correct each 0.1ppm of combined chlorine.  Failing to realize this amount actually contributes to the chlorine demand problem as more chloramines are formed.  We often hear the consumer complain that “my pool guy told me to put in a double dose of shock to treat my cloudy pool.”   That amount may indeed fall VERY short of the actual need.  When a chlorine demand test is performed, it is often necessary that a dose of 10, 20 or more times of chlorine shock is needed to reach breakpoint chlorination.  That means potentially adding 40, 50 or more pounds of shock (in the form of cal hypo) at one time! Yes, at one time!  If you try spreading it out (even over a few hours) you’ve defeated the cure and unwittingly added to the problem.

Remember, in spas & hot tubs it is usually more efficient to drain & refill than it is to shock with that quantity of chlorine.

We describe the problem this way to our customers in regards to reaching breakpoint or satisfying chlorine demand:  Reaching breakpoint chlorination is an “all or nothing” proposition. Think of it as trying to jump the Grand Canyon in a single bound; you can’t “come close”.  You MUST reach the other side FIRMLY.  You can’t “almost make it.”  Whether you’re 2 inches short or 100 feet short, you’re still short. 

Continue to page 2  

Translate this page or any of our pages using the tool below :