Chloramines - combined chlorine-
video on "Pool Shocking"
One of the most common causes of water related problems in 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. Chloramines 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).
But foul chlorine odors are just the ugly mask of the underlying problems present in swimming pool 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.
Basic water testing & water chemistry , as mentioned in
Key 4 and
Key 5 of the
5 Keys to Pool Care, is "key" to preventing chloramines
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
1.0 ppm 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.
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
where our constant reminding of consumers of the need to weekly “shock”
their chlorine or bromine pool. Weekly shocking during the entire time the pool
is open & operating will greatly reduce the potential of chlorine demand or
As of June 1, 2006 a new, state of the art Chlorine Demand test station (BioGuard®'s
Accu-Demand 30) is available to us & in our store. It is virtually 100% accurate.
Compared to the old method, results are now available in about 30 minutes rather
than 24 hours. This gets the problem rectified immediately, as opposed to
waiting an additional day or 2 when the results would be ready and more
chloramines form. The Accu-Demand 30 will be the best available method to
accurately perform a Chlorine Demand test on the market. If you are one of our
“out of town” customers, you can send a water sample for testing. There will be
a small fee for this service; however we will call you with the results and
recommendations within 3 hours of our receipt of the sample.
facet to the chlorine demand and chloramines problem is the misconception that
the pool “smells of chlorine,” therefore (in the novice’s mind) “I’ve got too
much chlorine or too many chemicals present in the water,“ and they stop adding
anything to the pool, effectively ignoring the problem. Testing goes out the
window; pH and overall water balance go out of balance. The pool owner is not
convinced that their true problem is a “lack” of chlorine and particularly FAC.
This is especially true if the homeowner or pool operator is using OTO
(orthotolodine will produce results for Total Chlorine only, using yellow color
standards, not differentiating the difference between FAC and chloramines
present) for chlorine testing as opposed to the more accurate DPD (using pink
color standards) method (uses separate tests for Free Chlorine as well as Total
Continued page 2
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