What’s in my water-source water testing?
It is important to test the source water before a new pool’s first fill, although it is often an afterthought after the initial fill. It is critical to know what the readings are of the source water to have the appropriate chemicals on hand to treat the water immediately after the initial fill. This saves valuable time and prevents potentially aggressive water from staining a new pool finish.
Many commercial and residential applications can have the source water go through a water softener before getting added to the pool. For example, on a recently finished high school pool project with a water volume of 1,854,852 L (490,000 gal), when testing the source water before filling, the calcium hardness was found to be 150 parts per million (ppm). Knowing this information, it was determined 353 kg (778 lbs) of 85 per cent calcium chloride (CaCl) had to be added to the water on the initial fill.
Having this water quality information is valuable because it can also be used to calculate an estimate of how much the owner will need on hand for a 30-day supply. In this case, the source water also indicated higher levels of copper and iron; therefore, a sequestering product was also added to the initial fill. By knowing the makeup of the source water, the operators now know when making their monthly chemical orders they should get slightly more calcium chloride as well as have a sequestering product on hand. Every pool will need fresh water added daily. It can be from a sophisticated water system controlled by sensors to add the water in automatically or from a simple garden hose.
Whichever way the fill water is added, it is better to be prepared by knowing what is in the water. It is a good idea to test the source water at a minimum once a month, more if possible. Municipal water can change and understanding even minimal changes can help operators determine what needs to be added to a pool to balance the water chemistry.
