Filling the pool with mains water
We recommend filling the pool with mains water. Rainwater or, for example, groundwater can give rise to unexpected reactions (such as turning the water brown) with pool chemicals. Information on the quality of mains water (including water hardness) can be obtained from your water supplier. Before you start adding chlorine to the water, it’s important to ensure that the pH of the water is between 7.2 and 7.6. You can test the pH with a swimming pool water testing kit. In the Netherlands, the pH of mains water is usually around 7.8. If need be, you should use pH Minus to lower the pH or pH Plus to raise the pH.