These days it is so easy to administer water quality testing that there is no excuse for you being concerned or doubtful about the quality of some source or body of water. The testing kits are relatively inexpensive, are easy to buy and they can be completed within a matter of minutes.
There are a number of key things that these kits test for.
The pH balance with regards to the water has an impact on how effective your chlorine is going to be in the water. Ideally you want to have a pH level of between 7.4 and 7.6.
Anything lower than 7.2 and it is more acidic and if it is greater than 7.8 you are dealing with more alkaline water.
Chlorine is vital in order to keep away harmful bacteria and pathogens that may infiltrate the water, causing sickness and other issues. Some people use bromine as an alternative to chlorine but whatever the case may be, you need to ensure that the levels found in your water are adequate to ensure that all harmful bacteria has been destroyed.
You want the alkalinity levels of the water to be somewhere in the range of 110 to 120 ppm. You will have a good idea already of the alkalinity after the pH tests as if one of these readings is low, then you know that the other one also will be the same.
Usually the chlorine that is administered will have significant alkalinity which will help to increase the overall levels whereas if you are using cyanuric acid based chlorine tablets then this will have the opposite effect and in fact lower the alkalinity of the water.
Cyanuric acid is a chlorine stabiliser that is used and ideally the reading of this should be in the range of 20 and 30 ppm. It is usually found in chlorine tablets and helps the levels remain consistent throughout the body of water rather than pooling in one particular area.