Chloramine is another name for combined chlorine. This occurs when free available chlorine residual combines with nitrogen-containing compounds such as urine, sweat or other ammonia by-products of swimmers and environmental contamination. Combined chlorine has a reduced rate of efficacy as a sanitiser, can cloud the water, and has a strong, unpleasant odour. It can also irritate the skin and eyes of swimmers.
Chloramines can result from a number of sources. Improper maintenance is probably the most common. Pools that are not shocked regularly begin to build up undesirable compounds, such as perspiration, suntan lotions, and urine, as well as some air-borne contaminants. Eventually, these compounds form combined chlorine.
To obtain the combined chlorine residual, subtract the free chlorine residual from the total chlorine residual. If all of the chlorine residual from the test is free, (total and free are equal), then there are no chloramines.
To eliminate chloramines:
- Apply 1 bag of Lite per 50,000 litres or 1 bag of Burn Out Extreme per 50,000 litres or 150 grams of Burn Out 35 per 10,000 litres for every ppm of combined chlorine present.
- Perform a chlorine demand test to determine the exact amount of chlorine needed to break up the combined chlorine.
Very high levels of chloramines can be a form of chlorine demand. Something is present in the water that is tying up the free chlorine residual and preventing it from working effectively. If there is not high combined chlorine, but there is an inability to maintain a free chlorine residual, perform the chlorine demand test and apply the quantity of product as indicated by the test.
If a chlorine demand test station or the rapid chlorine demand test is not available, this type of demand may be met by applying shock applications of 1 bag of Lite per 50,000 litres or 1 bag of Burn Out Extreme per 50,000 litres or 150 grams of Burn Out 35 per 10,000 litres according to label instructions. Test the chlorine residuals 12 – 24 hours later. If the free and total chlorine residuals are less than 3.0 ppm, perform the shock again. Continue to shock until residual of 3.0 ppm or more is present 12 to 24 hours after last shock application.
Drain 2.5 feet of water and dilute with fresh water to eliminate some of the demand.