Remember that swimming pools basically are large collections of water that are susceptible to various issues. Often, the water can give off strange or bad odors. The most common cause of funny smells in a swimming pool is chloramines, which result when pool chlorine combines with ammonia or nitrogen compounds like urine or sweat.
Chloramines are a part of that pool's combined chlorine reading, but they're not really chlorine and they're also very poor disinfectants, along with producing foul smells. Because of the way pool chlorine reacts with nitrogen or ammonia-containing substances, it produces chloramines as a kind of byproduct. Beside urine and sweat, chlorine also combines with nitrogen in rain or ammonia in swimmer saliva, among other substances.
If your pool smells funny and looks cloudy, chances are it has chloramines. Chloramine-heavy swimming pools frequently cause swimmers to complain of irritated skin. Another symptom is that the pool's combined chlorine reading will be above 0.2 parts per million (ppm). The formula to determine a pool's combined chlorine through a test kit is: Total chlorine level minus free chlorine level equals combined chlorine.
The best method for eliminating chloramines from a swimming pool is to shock, or superchlorinate, it. Pool professionals call what happens in a pool during superchlorination "breakpoint chlorination," and it's necessary to eliminate chloramines. Basically, a swimming pool in which chloramines are present will need to be superchlorinated to 10 ppm or more and held there for at least four hours. During superchlorination, actual chlorine is "burning up" or oxidizing chloramines and removing them from the swimming pool.
The best way to prevent chloramines is to maintain recommended chlorine levels and also to shock your pool regularly. The recommended range of chlorine in a pool is 1 to 2 ppm. Remember, though -- chlorine shock will raise pH because chlorine is alkaline. After a pool shock treatment has been completed, always measure pool pH and adjust if necessary. A swimming pool's pH should be held at 7.4 if possible.
The most important reading in a swimming pool's water is its pH, and it must be maintained at recommended levels. When a pool's pH is too low or too high, chlorine levels are always negatively affected. And that can cause many problems, including issues with chloramines. Raise a pool's pH by adding 1 pound of sodium carbonate per 25,000 gallons of water. Pool pH is lowered by using muriatic acid strictly according to package instruction.