POOL LAB PL25 - CHLORINE STABILIZER - CYANURIC ACID; Combined Chlorine - Chloramines

CHLORINE STABILIZER – CYANURIC ACID
The sun’s ultraviolet light breaks down chlorine rapidly, so in domestic applications it is
highly beneficial to use a chlorine stabilizer in pools with exposure to the sun. Indoor pools
will only benefit if there is direct sunlight on the water for a significant part of the day.
The importance of its use is such that our range of chlorinators are sized with the express
requirement that chlorine stabilizer be used as per the directions. Cyanuric acid or chlorine
stabilizer, when dissolved in the pool water to achieve levels of between 40ppm to 80ppm
will effectively reduce the breakdown of chlorine by ultraviolet light.
Higher stabilizer levels (greater than 100ppm) may in fact be detrimental to the pool water,
and will actually stop the chlorine from killing bacteria and algae effectively. Consult with
your local pool professional for the appropriate amount to use in your pool.
Combined Chlorine - Chloramines
A common cause for unusually high chlorine demand is the presence of chloramines in the
pool water, detectable when a Total Chlorine test result is higher than a Free Chlorine test
result by greater than 1.0ppm. The difference between these two test results is known as
the “Combined Chlorine”. More advanced test kits will include the Total Chlorine test,
otherwise you will need to have your water tested professionally to check for this.
Chloramines are formed when free chlorine reacts with ammonia like compounds called
'amines', and this will build up over time. Chloramines are a poor disinfectant and also
reduce the disinfecting power of the free chlorine in the water. Chloramines are irritating
to the eyes and respitory system, and are responsible for the “chlorine smell” most
noticeable around heavily used indoor pools.
As a general rule Pool Lab recommend shock dosing your pool with liquid chlorine at least
once every swim season as this can significantly reduce chlorine demand and greatly
improves the disinfecting power of the free chlorine in the water. For pools with heavier
bather loads this may need to be done more often.
An accurate measurement of the pool volume and combined chlorine level is essential for
calculating the required amount of chlorine to perform the shock dose.
You should consult your local swimming pool professionals for advice on this
procedure, and how often is appropriate for your pool.
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