Combined chlorine (Chloramines) and your swimming pool – What you need to know!
- red, burning eyes;
- burning sensation in nose, throat and lungs;
- dry, itchy skin and dry hair;
- breathing difficulty leading to "swimmers' asthma" particularly in young children.
In addition to these, the pool has a tendency to discolor, becoming milky or green with algae due to the low sanitizing ability of the combined chlorine.
Testing for combined chlorine in pool water
All good chlorine test kits and pool test strips allow you to determine free chlorine as well as total chlorine. Combined chlorine is calculated from these values as follows:
Combined Chlorine = Total Chlorine - Free Chlorine
The combined chlorine value should never exceed 50% of the free chlorine value and should ideally be as close to zero as possible.
Some cheaper test kits that use liquid reagents (drops) offer one value for the chlorine test. If the reagent bottle is marked "OTO" then you are only testing total chlorine and should consider a better test kit.